Physics Exam #1
A car is traveling at 22 m/s and slows to 4.3 m/s in 4.0 seconds. What is the acceleration? Give the answer to one decimal place.
-4.4 (a=v1-v2 /t)
A ball is thrown straight up from a bridge at a speed of 11.0 m/s. If it takes 5.5 seconds to hit the water below, what is the velocity just before it hits the water?
-43 m/s (V=vo + at; using v2 (-11) and t2 (3.26))
A bullet of mass 0.010 kg and speed of 100 m/s is brought to rest in a wooden block after penetrating a distance of 0.10 m. The work done on the bullet by the block is
-50 J (change in KE=work; KEfinal is zero (stopped); KEinitial is 1/2mv^2; 0-50= -50)
A runner can run a 400.0 meter lap in 50.0 seconds. He finishes at the same spot as he began. What is his average velocity?
0 m/s (acceleration has a direction)
How many meters are equal to 1.55 centimeters?
0.0155
27 cm = ____ m
0.27
329g = ____ kg
0.329
A racecar driver has to hold on tightly when going around a banked curve. How many "gs" does the driver experience in a 2200 kg car going around a circle with a radius of 95 meters at 25 m/s? given that ac=6.58
0.67 ("gs"= 9.8; ac/g= 6.58/9.8=0.67)
A spring with a force constant of 200 N/m is stretched 0.10 m from its equilibrium position. The potential energy of the spring increases by
1.0 J (PE=1/2 Kx^2; k is the force and x is the distance)
An athlete has a mass of 65 kg and a volume of 62 liters. What is the density is kg/l?
1.05
In an auditorium, a physics teacher uses a pendulum made by hanging a bowling ball from a wire to the ceiling. At the low point in its swing, a ball with a mass of 7.2-kg has a speed of 6 m/s. Ignoring air resistance, how high will the bob swing above the low point before reversing direction?
1.8 m
The metric system is based upon all prefixes being multiples of:
10
A box is moved 10 m across a smooth floor by a force making a downward angle with the floor, so that there is effectively a 10 N force acting parallel to the floor in the direction of motion and a 5 N force acting perpendicular to the floor. The work done is
100 J (ignore perpendicular; work=fd)
A 600.0 kg roller coaster is going around vertical loop with a radius of 10.0 meters. The speed of the coaster is 13m/s at the top of the loop. What it the magnitude of the CENTRIPETAL force on the roller coaster, to the nearest whole number of newtons?
10140 (ac=mv^2/r)
A man standing on a bridge throws a stone downward with a speed of 20 m/s. The stone hits the water below 3 s later. The bridge is approximately
104 m high (d=vot + 1/2 at^2)
An elevator has a mass of 1200.0 kg. It is rising at a steady speed of 3.00 m/s. What is the tension in the cable lifting the elevator?
11760 N (Tension - gravity = net force; force= ma and a is zero; solving for G:m *g--> 9.8*1200; solving for T: T-11760=0; T=11760)
What is the mass of a car that weighs 11,610 N?
1180 (F=ma)
An object has a net force of 60.0 N pulling on it and accelerates at 5.0 m/s2. What is the mass of the object?
12 kg (f=ma)
A 0.50 kg ball has a velocity of 22 m/s. What is the magnitude of the work done to stop the ball when you catch it?
121 J (KE=1/2mv^2)
An iron vise falls from rest at a great height. Neglecting air resistance, what distance has it fallen in the first 5 seconds?
122 m (D=1/2gt^2)
What is the weight of 83 kg student on moon where the acceleration of gravity is around 1.6 m/s2 ? (in newtons) Round your answer to the nearest whole number.
133
A 2400 kg truck is going around a curve with a radius of 80 meters. The speed of the truck is a constant 22 m/s/ What it the force on the truck, to the nearest whole number of newtons?
14520 (fc=mac)
A bomb is dropped from an airplane at a height of 1200 meters. How long will it take to hit the ground?
15.6 seconds (D=1/2gt^2; solve for t)
An elevator has a mass of 1200.0 kg. It is rising at a steady acceleration UPWARD of 3.00 m/s2 . What is the tension in the cable lifting the elevator?
15360 N (Tension - gravity = net force; force= ma; solving for G:m *g--> 9.8*1200; solving for T: T-11760=m (1200)(3))
A car traveling at 22.0 m/s decelerates for 2.53 seconds at a rate of -2.25 m/s2. What will the final speed be in m/s?
16.3 (v=vo + at)
A golf club head can be thought of as undergoing circular motion when you swing the club. If the club head has a mass of 0.65 kg, a speed of 24 m/s and a radius of 2.2 meters, (club length + arm length) what is the force on the club head due to the swing?
170 N (ac=v^2/r; solve for ac; fc=mac; solve for fc)
Suppose you climb the stairs of a ten-story building, about 30 m high, and your mass is 60 kg. The gravitational potential energy you gain is about
17540 Joule (PE=mgh)
A basketball player throws a 1.2 kg ball 15 meters into the air. What is the increase in potential energy?
176 joules (PE=mgh)
A basketball player throws a 1.2 kg ball 15 meters into the air. What was the work done by the player?
176 joules (w=fd; f=ma)
An elevator and rider have a mass of 1,800 kg combined. What is the tension force in the cable lifting them at a steady speed of 3 m/s? Assume no friction and round your answer to a whole number.
17640 (Net F= Tension - Gravity --> Net F= (m)(a); Gravity= (m)(g); so, (m)(a)= T - (m)(g) --> (1800)(0)= T - (1800)(9.8))
A 2200 kg car can accelerate from 0 to 30.0 m/s in 5.5 seconds. What is the power required?
180000 W
A racecar driver has to hold on tightly when going around a banked curve. Approximately what is the centripetal force on a 2,750.0 kg car going around a circle with a diameter of 190.0 meters at 25.0 m/s? (Units are newtons, but you do not type them in the blank.)
18092 N (diameter is 2x length of r; ac=v^2/r; solve for ac; fc=mac; solve for fc)
An elevator and rider have a mass of 1,500 kg combined. What is the tension force in the cable lifting them at a steady acceleration of 3.0 m/s2? Assume no friction. Round your answer to the nearest whole number.
19200 (Net F= Tension - Gravity --> Net F= (m)(a); Gravity= (m)(g); so, (m)(a)= T - (m)(g) --> (1500)(3)= T - (1500)(9.8))
A doctor orders 2000 ml of a saline IV drip. The bags contain one liter each. How many bags do you need?
2
2.02kg = ____ g
2,020
A 10-kg object dropped from a certain window strikes the ground in 2.0 s. Neglecting air resistance, a 5-kg object dropped from the same window strikes the ground in
2.0 s
An object has a mass of 24 kg. There is a net force of 60.0 N on the object. What is the acceleration of the object?
2.5 m/s^2 (a=f/m)
A car is goes from 0.00 to at 54.0 km/hr in 5.5 seconds. What is the acceleration in m/s2? Round the answer to one decimal place.
2.7 (convert then use A=v2-v1/t)
The acceleration due to the Earth's gravity, in English units, is 32 ft/s2. In the absence of air friction, a ball is dropped from rest. Its speed on striking the ground is exactly 60 miles/hr. For what time interval was the ball falling? (There are 5280 feet in one mile.)
2.75 s (convert 60 miles/per to ft/sec; v=vo + at)
A force of 25 newtons pushes a 5.0 kg wagon to the right. There is a friction force of 5.0 N. What is the net force?
20 N right
In order to find the depth of a well, you drop a stone into it and time its fall. It hits the water after falling for 2 s. The depth of the well is about
20 m (D=1/2at^2)
A roller coaster with people on board has a total mass of 4500 kg and starts at a height of 22 meters with a speed of 2.0 m/s. 50 kJ of work is done by friction on the way to the bottom of the ride. What is the speed at the bottom of the ride?
20 m/s (ME1-friction=ME2; ME1=PE +0; PE=mgh; =970200; 970200- friction (50)=970150; 970150=ME2 which is 1/2mv^2; solve for v)
A box is moved 10 m across a floor by a force of 20 N acting along the direction of motion. The work done by the force is
200 J.
A student in weight lifting class lifts 65 kg from the floor to a height of 1.6 m. It takes 5.0 seconds to do the work. How much power is needed, in watts?
204 (force= ma --> work= fd --> power=work/time)
A roller coaster has a 100.0 kg cart at the top of a 22.0 m ramp. As it goes down the ramp, it change 800.0 joules of energy to heat due to friction. What will the kinetic energy be at the bottom of the ramp?
20760 J (ME1-friction=ME2 --> ME1= 0 + PE --> PE=mgh; (100)(9.8)(22)-800J= ME2)
There are 12 tables in the classroom that must have new covers. Each table is 1.80 meters long. How many centimeters of material are needed to cover the length of all the tables?
2160
A projectile is launched horizontally from a height of 2.2 meters at 33 m/s. How far will it travel horizontally before it hits the ground?
22 (D=vot + 1/2 at^2; plug in distance, assume vo is zero and acceleration is 9.8; solve for t; D=vot + 1/2 at^2; acceleration is zero; solve for D)
A car travels at 75.0 km/hr for 3.00 hours. How many km will it travel?
225 km
An object has a mass of 24.0 kg and is accelerated horizontally at 4.0 m/s2. What is the weight of the object? (You may round the answer to whole numbers.)
235 N (w=mg; g=9.8)
A bomb is dropped from an airplane at a height of 1200 meters. The plane is flying horizontally at 160 m/s. About how far horizontally will the bomb fly before it hits the ground? (Time is 15.6 seconds bc of last problem)
2496 m (D=vot + 1/2 at^2; bc of horizontal, a=o; multiply 160 by 15.6)
A force of 10 newtons pushes a box 5 meters in 2 seconds. What is the power required?
25 W
A baseball is thrown horizontally from a height of 6 meters at a speed of 24 m/s. How far will it travel horizontally before it hits the ground?
26.6 m (For vertical, D=vot + 1/2 at^2; plug in 6, initial velocity is zero, and solve for t; for horizontal, D=vot + 1/2 at^2; acceleration is zero; solve for D)
A 600 kg roller coaster is going around vertical loop with a radius of 10 meters. The speed of the roller coaster is 12 m/s at the top of the loop. What it the magnitude of the NORMAL force on the roller coaster, to the nearest whole number of newtons?
2760 (N=mv^2/r - mg; solve for N)
A 1,500 kg car is being pushed by a force of 6500 N. There is a friciton force of 1500 N. What is the acceleration in m/s2 ? Give the answer to one decimal place.
3.3 (6500-1500=5000; 5000/1500=3.3; f=ma)
A car is driven down the road with a speed of 34 m/s for 15 minutes. How far will it travel in meters?
30,600 (v=d/t)
A car moving at 22.0 m/s accelerates at 3.00 m/s2 for 2.67 seconds. What will the final speed be in m/s?
30.0 (v=vo + at)
A force of F = 125 N is used to drag a crate 3.0 m across a floor. The force is directed at an angle upward from the crate so the vertical part of the force is Fv = 65 N and the horizontal part of the force is Fh = 107 N. How much work is done on the box?
321 J
A toy "spring gun" has a spring with a spring constant of 30,000 N/m and is depressed 4 cm. It shoots a plastic dart with a mass of 45 grams. How fast will the dart travel if there is no friction?
33 m/s (PE1 + KE1= PE2 + KE2; PE1 is 1/2kX^2, KE1 and PE2 is zero, and KE2 is 1/2mv^2; k=30,000; x= 0.04 m; mass=0.045)
Suppose you throw a ball vertically upward with a speed of 49 m/s. Neglecting air friction, what would be the speed of the ball 1.5 second later?
34 (v=vo + at)
A 5.0-kg cat runs to the left at 10 m/s and a 10-kg dog runs to the right at 5.0 m/s. The total kinetic energy is
375 J
A forensic scientist (CSI) is trying to find a weapon thrown off a bridge into the lake. Assume it is thrown horizontally and it sinks straight down once it hits the water. The bridge height is 15 meters and a normal throwing speed is 22 m/s. How far from the bridge should you search?
38 (D=vot + 1/2 at^2; plug in distance, assume vo is zero and acceleration is 9.8; solve for t; D=vot + 1/2 at^2; acceleration is zero; solve for D)
A 1,300 kg car accelerates at 3.0 m/s2 . What is the net force required? Round your answer to a whole number. Round your answer to the nearest whole number.
3900 (f=ma)
If the speed of a car is doubled, the work to stop the car changes by a factor of
4
If you double the speed of a car, how much does the kinetic energy increase?
4 times
A force of 25 newtons is to the right pushes on a 5.0 kg wagon. There is a friction force of 5.0 N. What is the acceleration?
4.0 m/s2 right
A 1,400 kg car is being pushed by a net force of 6500 N. What is the acceleration in m/s2 ? Give the answer to one decimal place.
4.6 (f=ma)
A runner travels 1.53 km in 5 min and 30 seconds. What is the velocity in m/s? Answer to two decimal places.
4.64 (convert --> V=d/t)
After 1 second, a ball dropped from rest will have fallen what distance?
4.9 m.
A sprinter accelerates at 5.0 m/s2. How far will she travel in 4.0 seconds if she starts at 0 m/s?
40 m (D=1/2 at^2)
An airplane is flying at 95.0 m/s when the engine is turned off. As it glides, it experiences a force of drag so that is slows down at -0.900 m/s2. How far in meters will it travel in 1.00 minute ?
4080 (D=vot + 1/2 at^2)
A 10 kg rock that has been dropped from a 60 meter high cliff experiences a average force of air resistance of 30 N. Calculate the KE at the bottom of the fall.
4080 J (ME1-work=ME2; ME1=PE + 0 --> mgh; work=fd)
41 m = ____ cm
4100 (cm=0.01)
4.3 m = ____ mm
4300 (milli=1000)
What angle of launch will give a projectile the maximum distance along the ground?
45
An iron vise falls from rest at a great height. Neglecting air resistance, what is its speed after it has fallen for 5 seconds?
49 m/s. (V=vo +at)
An object with a kinetic energy of 50 J is stopped in a distance of 0.01 m. The average force that stops the object is
5,000 N (change in KE=work; force=work/distance)
How many ml are in 5.3 cubic centimeters?
5.3 (1 mL=1 cm^3)
A car accelerates from 0.0 to 33 m/s in 6.0 seconds. What is the magnitude of the acceleration?
5.5 m/s^2
A car travels at 75 km/hrs. How long will it take to travel 420 km?
5.6 hours (420/75)
A woman does 200 J of work to move a table that weights 600 N across the floor for a distance of 4.0 meters. What is the magnitude of the force that the woman applied to the table if the force is applied in the horizontal direction?
50 N
A motor rated at 500 watts output is capable of performing _________________ joules of work in 10 seconds.
5000
Evaluate the formula: d = vt + ½ gt2 for d given v= 16.0 g = 10.0 t = 2.0
52
A 600 kg roller coaster is going around vertical loop with a radius of 10 meters. The speed of the coaster is 11 m/s at the top of the loop. What it the magnitude of the GRAVITATIONAL force on the roller coaster, to the nearest whole number of newtons? (This question looks at a different part of the previous quesion).
5880 (w=mg; w is the gravitational force)
A 2400 kg truck is going around a curve with a radius of 80 meters. The speed of the truck is a constant 22 m/s. What it the acceleration of the truck, to the nearest TENTH in m/s2?
6.1 (ac=v^2/r)
Suppose you throw a ball vertically upward with a speed of 49 m/s. Neglecting air friction, what would be the height of the ball be 1.5 second later?
62 (d=vot + 1/2 at^2)
A car traveling at 22.0 m/s accelerates for 2.53 seconds at a rate of 2.25 m/s2. How far will it travel in meters during this time?
62.9 (D= Vot + 1/2 at^2)
A rock dropped from a bridge takes 3.71 to hit the water. How high is the bridge in meters?
67.4 (D=vot + 1/2 at^2)
What is the mass of 71 kg student on moon where the acceleration of gravity is around 1.6 m/s2 ? Round your answer to the nearest whole number.
71
What is the weight of 75 kg student on Earth, in newtons?
735 (7.5 * 9.8; w=mg)
What is the power requried to lift 200 newtons 15 meters straight up in 4 seconds? Give the whole number answer in joules.
750
A car is traveling at 33.0 m/s when the driver uses the brakes to slow down to 29.0 m/s in 2.50 seconds. How many meters will it travel during that time?
77.5 m (find acceleration A=v1-v2/t and then find distance D=vot + 1/2 at^2)
A ball is thrown straight up from a bridge at a speed of 11.0 m/s. What will be its velocity (speed and direction) after 2.0 seconds?
8.6 m/s down (acceleration will be negative due to the ball being thrown up; so 9.8 will be -9.8 in V=vo +at)
An elevator has a mass of 1200.0 kg. It is rising at a steady acceleration DOWNWARD of -3.00 m/s2. What is the tension in the cable lifting the elevator?
8160 (Tension - gravity = net force; force= ma; solving for G:m *g--> 9.8*1200; solving for T: T-11760=m (1200)* a(-3))
An elevator and rider have a combined mass of 1200.0 kg. They are moving down at a steady acceleration DOWNWARD of -3.00 m/s2. What is the tension in the cable lifting the elevator and rider?
8160 N
A ball is thrown straight up from a bridge at a speed of 11.0 m/s. If it takes 5.50 seconds to hit the water below, how high is the bridge?
88.0 m (v=vo + at solve for t1=2.24 and then t2 is 5.5- 2.24=3.26; d=vot + 1/2 at^2)
A man has a mass of 72.0 kg and is accelerating upward in an elevator at 2.50 m/s2. What is the normal force on his feet in newtons?
886 (m*a =fn -fg; m=83; a=2.5; fg=m (83) * a (9.8)=813.4)
A roller coaster with a mass of 500.0 kg starts from a height of 27.0 meters with a speed of 5.5 m/s. It descends to a height of 2.00 meters before it starts back up. Some energy is loss to the work due to friction. The speed at the bottom of the ramp is 22.0 m/s. How much energy was lost to friction?
9,100 J
A water balloon with a mass of 1.20 kg is falling from a roof. If the average force of friction is 0.500 N, what is the acceleration on the balloon in m/s2?
9.38 m/s2 down (net forces= mass * acceleration; net forces= force due to friction subtracted by force due by gravity; solving for gravity is (w=mg); plug in and solve for A)
An object has a mass of 24.0 kg and is accelerated horizontally at 4.0 m/s2. What is the force required?
96 N (F=ma)
Ball A is thrown upward with a velocity of 19.6 m/s. Two seconds later ball B is thrown upward with a velocity of 9.8 m/s. Which ball is first to return to the thrower's hand?
A and B will arrive at the same time (solve for A and B separately; A is 2 seconds, B is 1 second; time of descent of A is equal to flight of B)
An object falling near the Earth shows constant ___ if friction is insignificant. -velocity -speed -displacement -acceleration
Acceleration
When looking at a velocity versus time graph, what does the slope represent?
Acceleration
An object has 4 forces acting on it which balance in pairs. How will it behave?
At rest or moving at constant speed in a straight line.
A 20 N ball and a 40 N ball are dropped at the same time from a height of 10 meters. Air resistance is negligible. Which of the following statements is accurate? -The heavy ball has a greater acceleration and falls faster. -The light ball has a greater speed since it can accelerate faster than the heavy ball. -After 1 second has elapsed, both balls have the same kinetic energy since they have the same acceleration. -Both balls hit the ground at the same time but gravity does more work on the heavy ball than on the light ball.
Both balls hit the ground at the same time but gravity does more work on the heavy ball than on the light ball.
Two identical laboratory carts are rolling down a downhill ramp. There is no significant friction. One cart is loaded with an additional 500 grams. Which statement is correct? The heaviest cart will have more acceleration. The lighest cart will have more acceleration. Both carts will have the same acceleration. Neither cart will have an acceleration.
Both carts will have the same acceleration.
In a laboratory on Earth, all the air is pumped from a large tube. A feather and a steel ball are simultaneously released from rest inside the tube. What happens next?
Both objects fall and hit the bottom at the same time
The magnitude of work is equal to the _____ Kinetic Energy if the Potential Energy is constant
Change in
How is circular motion different than rotary motion? -Circular motion involves a small object (that can be considered a point) circling a center. It only has one linear speed. Rotary motion is a solid object, with each part having a different linear speed. -Circular speed is toward the outside and rotary speed is toward the inside. -They are two names for the exact same thing. -Rotary motion involves a small object (that can be considered a point) circling a center. It only has one linear speed. Circular motion is a solid object, with each part having a different linear speed.
Circular motion involves a small object (that can be considered a point) circling a center. It only has one linear speed. Rotary motion is a solid object, with each part having a different linear speed.
Energy is ___, it is not created or destroyed, in most instances.
Conserved
If the force of an engine of a rolling car becomes equal to the force of drag or friction on the car, what will the motion of the car be? constant velocity constant acceleration constant deceleration stopped
Constant velocity
Initially, a blue automobile has twice the kinetic energy that a red automobile has. Both are braked to a stop; both have the same amount of braking force. The red auto will stop in ____________________ as the blue auto.
Half the distance
3 railroad cars with equal masses and equal frictions are pulled by an engine. Where will the greatest tension be?
In the hook between the engine and the first car.
A brick slides across a horizontal rough surface and eventually comes to a stop. What happened to the kinetic energy of the brick? It was converted to other energy forms, mostly heat. It was simply destroyed in the process of stopping. Nothing, it is still in the brick but is now called potential energy. It was converted to a potential energy of friction.
It was converted to other energy forms, mostly heat.
Contrast and compare mass and weight. -They are basically the same thing. -They both have different symbols, but they have the same units. -Weight is the quantity of matter, and does not change, while mass depends upon weight and gravity, and can change with location. -Mass is the quantity of matter, and does not change, while weight depends upon mass and gravity, and can change with location.
Mass is the quantity of matter, and does not change, while weight depends upon mass and gravity, and can change with location.
A student carries a box horizontally across a room at constant speed. Has he done any work on the box? Yes, since weight is a force Yes, because you get tired. No since the force is at a right angle to the displacement. Yes since there is a force and a distance involved.
No since the force is at a right angle to the displacement.
You think you buy power from the Power Company. If you check your bill you pay by the kilowatt-hour. Is the kilowatt-hour a unit for power?
No; it is work unit or an energy unit, since it is equal to Power * time. Power = Work/time Work = Power * time
Which is NOT a branch of physics? Thermodynamics, waves, mechanics, and organic.
Organic
In our Physics class, we use __________ notation.
Scientific
A car is rolling downhill at a constant speed. Which of the statements below is/are true? -Only gravity is affecting the car. -Since there is a steady velocity, there is probably a force of friction that is equal but opposite to the component of the force of gravity down the hill. -Since there is no acceleration, there are no forces on the car. -Since there is a steady velocity, there is no friction.
Since there is a steady velocity, there is probably a force of friction that is equal but opposite to the component of the force of gravity down the hill.
If two vectors have different magnitudes and opposite directions, what is the sum of the two vectors. -Draw a right triangle, with the larger vector to the right and the smaller vector down. Then connect the tip to the tail. -Just add the magnitudes and keep the direction of the larger vector. (add the vectors but with both of them positive.) -Just add the magnitudes and keep the direction of the smaller vector vector. (add the vectors but with both of them positive.) -Subtract the magnitudes and keep the direction of the larger vector. (add the vectors but make one of them negative.)
Subtract the magnitudes and keep the direction of the larger vector. (add the vectors but make one of them negative.)
A ball is thrown straight up. It reaches its highest point and then falls back. Which of the following is the correct statement? -At the highest point in its motion, the ball's acceleration is zero -The acceleration on the ball is always -9.80 m/s2 . -At the highest point in its motion, the ball's velocity and acceleration are zero. -The acceleration is positive going up and negative going down -Throughout its motion, the ball's acceleration is zero.
The acceleration on the ball is always -9.80 m/s2 .
How is energy lost (not destroyed) in automobiles? -The energy is "lost" to the car but it has just moved into the environment, often as heat. -The chemical energy of the gasoline is changed completely to mechanical energy of the car going down the road. -The mechanical energy of the gasoline is changed completely to chemical energy of the car going down the road. -All of these are true.
The energy is "lost" to the car but it has just moved into the environment, often as heat.
A block sits on a slight incline, held at rest by the frictional force between the block and the incline. Which of the following statements is true? -The work by the frictional force is equal to the gravitational potential energy of the block. -The frictional force performs no work since there is no motion of the block. -The work done by gravity is entirely converted into heat because of the friction present. -The work done by the frictional force is negative since the force of friction opposes the direction that the block is being tugged by gravity.
The frictional force performs no work since there is no motion of the block
Three railroad cars are pulled by a train engine at a constant speed. How does the tension pulling the last single car compare to tension pulling all three of the cars. There is friction involved. -The tension pulling 3 cars is much greater than the tension pulling the one car. -The tension pulling 3 cars is the same as the tension pulling the one car. -Since there is no acceleration there is no tension. -All of these are true
The tension pulling 3 cars is much greater than the tension pulling the one car
A ball is rolled across a table and flies off the end. At that point it becomes a projectile. Which statement is correct? -The time of the flight is determined ONLY by the height of the table. -If you roll the ball faster, it will stay in the air longer. -The distance of the flight is determined ONLY by the speed of the ball across the table. The height does not matter. -If you roll the ball slower, with will travel further.
The time of the flight is determined ONLY by the height of the table.
What is meant by conserved, in conservation of energy? -Energies always add up. -Energy cannot change types. -We should always respect the environment. -The total amount of energy at the beginning is the same as the total amount of energy at the end, but the type of energy may change.
The total amount of energy at the beginning is the same as the total amount of energy at the end, but the type of energy may change.
Sometimes, when students read a question where the speed is increasing at a steady rate, they will say the acceleration is increasing also. However, the acceleration is the same. For acceleration that does not change we use a lot of different words. Which of the answers does NOT mean it does not change? -variable -constant -uniform -steady
Variable
We calculate net forces using plus and minus because force is a ____.
Vector
When looking at a displacement versus time, what does the slope represent?
Velocity
According to Physics, what is the DIFFERENCE between speed and velocity? -They both have the same units. -Velocity has direction and speed does not. -Speed is in miles/hour and velocity must be in meters/second -There is no difference
Velocity has direction and speed does not.
Virgil rides a skateboard (combined mass 100 kg) at 4 m/s, and Jill rides a bicycle (combined mass 64 kg) at 5 m/s. Virgil has the greater kinetic energy. Virgil and Jill have equal kinetic energies. Jill has the greater kinetic energy.
Virgil and Jill have equal kinetic energies.
Jim exerts a force of 500 N against a 100-kg desk that does not move. Virgil exerts a force of 400 N against a 60-kg desk that moves 2 m in the direction of the push. Mik exerts a force of 200 N against a 50-kg desk that moves 4 m in the direction of the push. The most work is done by
Virgil and Mik, who do equal amounts of work.
A law of science it often a predictor of what?
What will happen based upon past experiments
In the formula for power, power is equal to ____ divided by time.
Work; although you must remember that work is equal to change in energy, so you can use change in energy over time.
Solve for a: d = 1/2 at^2
a = 2d/t2
In projectile motion, the horizontal component of the motion has constant velocity, and the vertical component has constant ___.
acceleration
A named scientific theory is most correctly described as: - a scientist best guess based upon available data - the same thing as a scientific law. - an explaination of phenomenon that has been tested and verified by many scientists and/or many experiments - an absolute truth
an explaination of phenomenon that has been tested and verified by many scientists and/or many experiments
Neglecting friction, if a Cadillac and Volkswagen start rolling down a hill together, the heavier Cadillac will get to the bottom: before the VW at the same time as the VW after the VW
at the same time as the VW
Assuming they have the same amount of friction, if a massive Cadillac and light Volkswagen start rolling down a hill together, the heavier Cadillac will get to the bottom: after the VW at the same time as the VW before the VW
before the VW
A 1600 kg car moving at 22 m/s is in a wreck with a 2900 truck moving at 32 m/s in the opposite direction. Which exerts a greater magnitude of force on the other?
both exert the same force
In which of these paths may the speed stay the same for the entire motion? projectile in gravity; as in a thrown ball parabola; as in projectile motion circular; As in a car going around a curve accelerated; as a car going from 0 mph-60mph
circular; as in a car going around a curve
In horizontal projectile motion free from friction but not free of gravity, the horizontal velocity is: -the horizontal velocity is constant and the vertical acceleration is constant. -the horizontal velocity is increases and the vertical velocity increases. -the horizontal velocity is constant and the vertical acceleration decreases. -the horizontal velocity is constant and the vertical acceleration increases.
constant and the vertical acceleration is constant.
Net forces cause accelerations and inertia is related to _____. -constant velocity -constant acceleration -variable acceleration -variable velocity
constant velocity
Vectors must include magnitude and
direction
A body released from rest falls with an acceleration of 9.8 m/s². If the same body is thrown upward at an angle, and air resistance is negligible, its acceleration will be: downward, and less than 9.8 m/s2 . upward, and equal to 9.8 m/s2 . downward, and equal to 9.8 m/s2. downward, and greater than 9.8 m/s2 . upward, and greater than 9.8 m/s2.
downward, and equal to 9.8 m/s2.
A ball dropped in the absence of air resistance accelerates downward at -9.8 m/s2. If instead you throw the ball upward, then the acceleration after its release is: equal to 9.8 m/s2. greater than -9.8 m/s2. equal to -9.8 m/s2. less than -9.8 m/s2.
equal to -9.8 m/s2.
Although the word "theory" can be used in everyday language in a general way, a named scientific theory should be supported by: - an individual with a lot of research - opinions - experimentation confirmed by many people - a math formula
experimentation confirmed by many people
Which is the metric unit for mass?
gram
An elevator is lifting a person up with an acceleration of 3 m/s2. The tension in the lifting wire due to the person is: less than the force of gravity on the person greater than the force of gravity on the person equal to the force of gravity on the person
greater than the force of gravity on the person
In projectile motion, the range is the horizontal component, and the ____ is the vertical component.
height or altitude
The acceleration of an object is proportional to the force upon the object and __________ to the mass of the object
inversely proportional
The acceleration of an object is ___________ the mass of an the object if the force remains the same. inversely proportional to greater than equal to proportional to
inversely proportional to
Which would be the best prefix to use for 135,000 meters to give it the must reasonable size number?
kilo
Which is not a unit of force? Newton, kilogram, pound
kilogram
What are the units for centripetal acceleration?
m/s^2
The word physical in physical science and the word significant in significant figures both refer to the concept of: - math - scientific - biological - measurable
measurable
A refrigerator weighing 1500 N is to be lifted onto a truck bed that is 1.0 m above the ground. When pushed up a slanting ramp 2.0 m in length a force of only 800 N is required to move it at constant velocity. Comparing the work involved in lifting the refrigerator straight up to the work in pushing it along the ramp, there is
more work required when the ramp is employed (work=fd; 1500 * 1= 1500; 800 * 2= 1600; ramp is more)
What describes the motion of an object thrown straight up into the air? Take up to be positive.
negative acceleration going up, negative acceleration at the top, and negative acceleration going down (acceleration = m/s^2)
Which of these is NOT common to all forces? unbalanced or net forces create accelerations units of kg m/s2 units of newtons net forces produce constant velocity
net forces produce constant velocity
What do we call a force that supports a person standing on a floor?
normal
Work is not being done on an object unless the
object is moving
What is the path of a projectile launched in a gravitational field? displacement straight line circular parabola
parabola
The friction force always points: perdicular down to the surface perdicular up to the surface parallel to the velocity of the object, but in the opposite direction in the same direction as the object moves
parallel to the velocity of the object, but in the opposite direction
Which of the following is not a metric unit? -meter -gram -pound -second
pound
The acceleration of an object is ___________ the net force on the object. inversely proportional to greater than equal to proportional to
proportional to
The sum of two or more vectors is called the
resultant
Two mountain bikers are rolling down a hill. They both have the same mass, but one is taller and has more air drag (friction, etc.) than the shorter one. Which will reach the bottom first?
short person
The resultant of two vectors that are in non-parallel directions (at an angle) can be solved by: division addition of the positive magnitudes multiplication solving graphically (draw to scale)
solving graphically (draw to scale)
A car going around a curve hits a slick spot. What will be the direction of the slide? toward the center of the curve away from the center of the curve straight ahead parabola
straight ahead
The resultant of two vectors that are in opposite directions can be solved by: subtraction multiplication addition of the positive magnitudes division
subtraction
What do we call a force that follows a string or a rope?
tension
A bat hits a ball. What is the reaction force of the action reaction pair? The ball hits the bat. The ball flies away The bat stops moving All of these
the ball hits the bat
a predictor of what will happen based upon past experiments.
the law is based upon observation or experiments
What is meant by signficant figures? - the number of reliable digits that can be measured - a graphic or shape that helps explain phenomenon - it is another name for scientific notation - all of the above
the number of reliable digits that can be measured
The number of significant figures in a measurement should depend upon:
the precision of the equipment, i.e. the number of decimals marked on the ruler.
The force of gravity upon a small object near the planet depends upon: the mass of the large planet only the product of the mass of the planet and the mass of the object the sum of the mass of the planet and the mass of the object the mass of the small object near the planet only
the product of the mass of the planet and the mass of the object
The power of an engine is a measure of
the rate at which it can perform work.
Two college students are sliding down a hill on excellent sleds so you can ignore friction. One has a mass of 85 kg and one has a mass of 75 kg. Which will reach the bottom of the hill first?
they will both reach at the same time.
Another word for kilo is
thousand
In circular motion, the acceleration is ____ if you have a constant speed going around the circle.
toward the center
In circular motion, the force is ____ if you have a constant speed going around the circle.
toward the center
Circular motion is caused by a force that points _______________, toward the center of the circle straight out from the center tangent to the circle toward the outer part of the circle (away from the center)
toward the center of the circle
Solve: d = 1/2 gt2 + vt for v
v = d/t - 1/2 gt
You toss a ball straight up in the air. At the highest point, the ball's: -acceleration is zero but not its velocity. -velocity is zero and the acceleration is downward. -velocity and acceleration are zero. -velocity is zero and the acceleration is upward.
velocity is zero and the acceleration is downward.
In projectile motion, the ___ component uses 9.8 m/s2.
vertical
Which of the following is a force? -weight -mass -displacement -centripetal acceleration
weight