Physics final
A race car circles 10 times around a circular 8.0-km track in 20 min. Using SI units(a) what is its average speed for the ten laps?(b) what is its average velocity for the ten laps?
(a) 67m/s (b) 0
A ball is thrown straight up with a speed of 36 m/s. How long does it take to return to its starting point, assuming negligible air resistance?
7.3 s
A ball is thrown downward from the top of a building with an initial speed of 25 m/s. It strikes the ground after 2.0 s. How high is the building, assuming negligible air resistance?
70 m
If I weigh 741 N on Earth at a place where g = 9.80 m/s2 and 5320 N on the surface of another planet, what is the acceleration due to gravity on that planet?
70.4 m/s2
A laser is thrown upward with a speed of 12 m/s on the surface of planet X where the acceleration due to gravity is 1.5 m/s2 and there is no atmosphere. How long does it take for the laser to reach the maximum height?
8.0 s
An object starts from rest at time t = 0.00 s and moves in the +x direction with constant acceleration. The object travels 12.0 m from time t = 1.00 s to time t = 2.00 s. What is the acceleration of the object? The tutorial is not clear here. Try first without looking at hint. hint: you don't know the speed at t=1s. It is not 0. at t = 1s, you have x1= 0.5 (a) (t^2) = 0.5 (a) (1) at t= 2s, you have x2 = 0.5 (a) (t^2) = 0.5 (a) (4) x2-x1 = 12 = 2a - a/2.
8.00 m/s2
A ball thrown horizontally from a point 24 m above the ground, strikes the ground after traveling horizontally a distance of 18 m. With what speed was it thrown, assuming negligible air resistance?
8.1 m/s
If you are driving 72 km/h along a straight road and you look to the side for 4.0 s, how far do you travel during this inattentive period?
80 m
If you are driving 72 km/h along a straight road and you look to the side for 4.0 s, how far do you travel during this inattentive period?hint: convert km to m and hours to second. (or use3.6km/h = 1m/s )
80 m
A girl of mass 55 kg throws a ball of mass 0.80 kg against a wall. The ball strikes the wall horizontally with a speed of and it bounces back with this same speed. The ball is in contact with the wall What is the magnitude of the average force exerted on the wall by the ball?
800 N
If you run a complete loop around an outdoor track of length 400 m in 100 s, find your(a) average velocity and (b) average speed.
a) 0 (b) 4 m/s
A ball bounces of a ball as shown. The interaction lasts for 0.1s What is the acceleration of the ball? (use the definition of acceleration and integers) acceleration is a vector
-200m/s/s
A mosquito flying at 3 m/s that encounters a breeze blowing at 3 m/s in the opposite direction has a speed of (relative to Gnd) hint: swimming counter current.
0
Molly leaves its hide and walks 5 inches to grab a cricket. She then go back to her hide. It takes 5s for the ROUND TRIP. ROUND TRIP/ Her average velocity (VELOCITY)
0
The position x(t) of a particle as a function of time t is given by the equation x(t) = (3.5 m/s)t - (5.0 m/s2)t2. What is the average velocity of the particle between t = 0.30 s and t = 0.40 s?
0 m/s
A ball is projected upward at time t = 0 s, from a point on a flat roof 10 m above the ground. The ball rises and then falls with insignificant air resistance, missing the roof, and strikes the ground. The initial velocity of the ball is Consider all quantities as positive in the upward direction. At time the vertical velocity of the ball is closest to
0 m/s.
A mosquito flying at 3 m/s that encounters a breeze blowing at 3 m/s in the opposite direction has a speed of
0 m/s.
A polar bear starts at the North Pole. It travels 1.0 km south, then 1.0 km east, and then 1.0 km north to return to its starting point. This trip takes 45 min. What was the bear's average velocity?
0.00 km/h
Two ice skaters suddenly push off against one another starting from a stationary position. The 45-kg skater acquires a speed of 0.375 m/s relative to the ice. What speed does the 60-kg skater acquire relative to the ice?
0.28 m/s
A car is traveling north at After 12 s its velocity is in the same direction. Find the magnitude and direction of the car's average acceleration.hint: Draw the situation. 14.1m/s is the final velocity. So you see, its slowing down. acceleration has the same direction as the force.
0.30 m/s2, south
A 0.140-kg baseball is dropped and reaches a speed of 1.20 m/s just before it hits the ground and bounces. It rebounds with an upward velocity of 1.00 m/s. What is the change of the ball's momentum during the bounce?hint: remember the sign. up is + and down is -.
0.308 kg ∙ m/s upwards
A 0.14-kg baseball is dropped from rest from a height of 2.0 m above the ground. What is the magnitude of its momentum just before it hits the ground if we neglect air resistance?hint: use kinematics to find the speed before it hits the floor. REmemberVf2=Vi2 - 2(9.8)h . then use the definition of momentum
0.88 kg ∙ m/s
A 0.140-kg baseball is thrown with a velocity of It is struck by the bat with an average force of 5000 N, which results in a velocity of 37.0 m/s in the opposite direction from the original velocity. How long were the bat and ball in contact?
1.79 × 10-3 s
A ball is thrown with an initial velocity of 20 m/s at an angle of 60° above the horizontal. If we can neglect air resistance, what is the horizontal component of its instantaneous velocity at the exact top of its trajectory?
10 m/s
An apple falls from a tree and hits the ground 5 meters (-5) below with a speed of about hint: use the 4th equation. V^2 = Vo^2 +2(-10) (displacement) .
10 m/s.
An object falls freely from rest on a planet where the acceleration due to gravity is 20 m/s2. After 5 seconds, the object will have a speed of
100 m/s.
A 400 lbs car is on the surface of the EArth (distance R from center). At a distance 2R the weight of the car is
100lbs
The x component of vector is 8.7 units, and its y component is -6.5 units. The magnitude of is closest to
11 units.
Oliver is speeding up to catch the bus. at t=0 his speed was 1m/s (V0). His acceleration is 2m/s/s. He runs for 10s. X=0 at t= 0 . So when you start the stop watch, x=0 and Vo=1m/s His displacement is
110m
A runner maintains constant acceleration after starting from rest as she runs a distance of 60.0 m. The runner's speed at the end of the 60.0 m is 9.00 m/s. How much time did it take the runner to complete the 60.0 m distance?
13.3 s
A 480-kg car moving at 14.4 m/s hits from behind a 570-kg car moving at 13.3 m/s in the same direction. If the new speed of the heavier car is 14.0 m/s, what is the speed of the lighter car after the collision, assuming that any unbalanced forces on the system are negligibly small?hint: use m1V1+m2V2=m1V1'+ m2V2'
13.6 m/s
A car accelerates from to at a rate of How far does the car travel while accelerating?
133 m
A vector has components Ax = 12.0 m and Ay = 5.00 m.(a) What is the angle that vector makes with the +x-axis?(b) What is the magnitude of vector ?
A 328-kg car moving at 19.1 m/s in the +x direction hits from behind a second car moving at in the same direction. If the second car has a mass of and a speed of right after the collision, what is the velocity of the first car after this sudden collision?hint: Before they go in the same direction. Use m1V1 + m2V2 = m1 V1'+ m2 V2'
14.0 m/s
A car is traveling with a constant speed when the driver suddenly applies the brakes, causing the car to slow down with a constant acceleration of magnitude 3.50 m/s2. If the car comes to a stop in a distance of 30.0 m, what was the car's original speed?
14.5 m/s
A car is traveling with a constant speed when the driver suddenly applies the brakes, causing the car to slow down with a constant acceleration of magnitude 3.50 m/s2. If the car comes to a stop in a distance of 30.0 m, what was the car's original speed?hint: slwoing down means the acceleration is negative.
14.5 m/s
A boy jumps with a velocity of magnitude 20.0 m/s at an angle of 25.0° above the horizontal. What is the horizontal component of the boy's velocity?
18.1 m/s
A car is traveling at 26.0 m/s when the driver suddenly applies the brakes, causing the car to slow down with constant acceleration. The car comes to a stop in a distance of 120 m. How fast was the car moving when it was 60.0 m past the point where the brakes were applied?
18.4 m/s
A car is traveling at 26.0 m/s when the driver suddenly applies the brakes, causing the car to slow down with constant acceleration. The car comes to a stop in a distance of 120 m. How fast was the car moving when it was 60.0 m past the point where the brakes were applied?hint: we did it in class.
18.4 m/s
A car starts from rest and accelerates with a constant acceleration of 1.00 m/s2 for 3.00 s. The car continues for 5.00 s at constant velocity. How far has the car traveled from its starting point?
19.5 m
You are driving home on a weekend from school at 55 mi/h for 110 miles. It then starts to snow and you slow to 35 mi/h. You arrive home after driving 4 hours and 15 minutes. How far is your hometown from school?
190 mi
Molly (my gecko) walks 3 inches @ east then 5 inches@ west. Her displacement is about
2 inches @ west
A stone is thrown with an initial upward velocity of 7.0 m/s and experiences negligible air resistance. If we take upward as the positive direction, what is the velocity of the stone after 0.50 s?
2.1 m/s
A 1200-kg cannon suddenly fires a cannonball at What is the recoil speed of the cannon? Assume that frictional forces are negligible and the cannon is fired horizontally.
2.9 m/s
Acceleration is sometimes expressed in multiples of g, where is the acceleration of an object due to the earth's gravity. In a car crash, the car's forward velocity may go from to in How many g's are experienced, on average, by the driver?hint: divide the acceleration by 9.8 to find gs.
20 g
The average speed of a horse that gallops 10 kilometers in 30 minutes is
20 km/h.
A girl throws a rock horizontally, with a velocity of 10 m/s, from a bridge. It falls 20 m to the water below. How far does the rock travel horizontally before striking the water, assuming negligible air resistance?
20 m
A player throws a football 50.0 m at 61.0° north of west. What is the westward component of the displacement of the football?
24.2 m
A 400-kg box is lifted vertically upward with constant velocity by means of two cables pulling at 40.0° on either side of the vertical direction. What is the tension in each cable?
2560 N
An object moves 15.0 m north and then 11.0 m south. Find both the distance it has traveled and the magnitude of its displacement.
26.0 m, 4.0 m
A dragster starts from rest and travels 1/4 mi in 6.70 s with constant acceleration. What is its velocity when it crosses the finish line?
269 mi/h
A car travels 20 km west and then 20 km south. What is the magnitude of its displacement vector? from origin. walk 20 @ left. then 20 @ down. connect the starting point to end point. You get a triangle. Use pythagorian theorem
28 km
You throw a rock horizontally off a cliff with a speed of 20 m/s and no significant air resistance. After , the magnitude of the velocity of the rock is closest to hint: Vx= stays the same. Vy=0 at t=0 but Vy=20m/s at t =2s. So find the magnitude with Pythagorean theorem
28 m/s.
A racquetball strikes a wall with a speed of 30 m/s and rebounds in the opposite direction with a speed of 26 m/s. The collision takes 20 ms. What is the magnitude of average acceleration of the ball during the collision with the wall? (the magnitude of the acceleration is asked. so do not include the negative sign)
2800 m/s2
At what value of t is the speed of the particle equal to 0 m/s? hint: the slope is 0 (horizontal tangent)
3 s
A runner ran the marathon (approximately 42.0 km) in 2 hours and 57 min. What was the average speed of the runner in m/s?
3.95 m/s
The lug nuts on a car wheel require tightening to a torque of 90 N ∙ m. If a 30-cm long wrench is used, what is the magnitude of the minimum force required using the wrench?
300 N
If a rocket initially at rest accelerates at a rate of 50 m/s2 for one minute, its speed will be
3000 m/s.
The components of vector are given as follows:Ax = +6.1Ay = -8.6The angle measured counterclockwise from the x-axis to vector , in degrees, is closest to:
305
The x component of vector is 5.3 units, and its y component is -2.3 units. The angle that vector makes with the +x-axis is closest to hint from origin. run 5.3 @ right. Then fall 2.3 @ down. Connect the starting point to ending point. It makes a triangle. What is the angle with the +xaxis. See my tutorial. step by step Use tangent.
340°.
The x component of vector is 5.3 units, and its y component is -2.3 units. The angle that vector makes with the +x-axis is closest to hint: you can trace the vector in the polar graph. Then use tangent to find the angle with +x-axis
340°.
An object is moving in a straight line with constant acceleration. Initially it is traveling at 16 m/s. Three seconds later it is traveling at 10 m/s. How far does it move during this time?
39 m
An airplane increases its speed at the average rate of 15 m/s2. How much time does it take to increase its speed from 100 m/s to 160 m/s?
4.0 s
A ball rolls across a floor with an acceleration of 0.100 m/s2 in a direction opposite to its velocity. The ball has a velocity of 4.00 m/s after rolling a distance 6.00 m across the floor. What was the initial speed of the ball?
4.15 m/s
A car initially traveling at 60 km/h accelerates at a constant rate of 2.0 m/s2. How much time is required for the car to reach a speed of 90 km/h?
4.2 s
A 0.10-kg ball, traveling horizontally at 25 m/s, strikes a wall and rebounds at 19 m/s. What is the magnitude of the change in the momentum of the ball during the rebound?
4.4 kg ∙ m/s
Which of the following quantities has units of a displacement? (There could be more than one correct choice.
40 km southwest 186,000 mi
A golf club exerts an average horizontal force of 1000 N on a 0.045-kg golf ball that is initially at rest on the tee. The club is in contact with the ball for 1.8 ms. What is the speed of the golf ball just as it leaves the tee?
40 m/s
the weight is 100N. The pull is 60N. The normal force (support force is)
40N
A velocity vector has components 36 m/s westward and 22 m/s northward. What are the magnitude and direction of this vector? For the direction, give the angle from the + x-axis . See tutorial
42m/s@149
A laser is thrown upward with a speed of 12 m/s on the surface of planet X where the acceleration due to gravity is 1.5 m/s2 and there is no atmosphere. What is the maximum height reached by the laser?
48 m
A bullet shot straight up returns to its starting point in 10 s. What is the initial speed of the bullet, assuming negligible air resistance?
49 m/s
A 1000-kg whale swims horizontally to the right at a speed of 6.0 m/s. It suddenly collides directly with a stationary seal of mass 200 kg. The seal grabs onto the whale and holds fast. What is the speed of these two sea creatures just after their collision? You can neglect any drag effects of the water during the collision.
5.0 m/s
A light-year is the distance that light travels in one year. The speed of light is 3.00 × 108 m/s. How many miles are there in one light-year? (1 mi = 1609 m, 1 y = 365 d)
5.88 × 1012 mi
A piano mover raises a 1000-N piano at a constant speed using a very light rope in a frictionless pulley system, as shown in the figure. With what force is the mover pulling down on the rope?
500 N
A 1200-kg ore cart is rolling at 10.8 m/s across a flat friction-free surface. A crane suddenly drops of ore vertically into the cart. How fast does the cart move just after being loaded with the ore?hint: its a collision hit and stick. But along the horizontal the load is not movingso m1 V1 + 0 = (m1+m2) V
6.30 m/s
A 1200-kg car moving at suddenly collides with a stationary car of mass If the two vehicles lock together, what is their combined velocity immediately after the collision?
6.9 m/s
If I weigh 824 N on Earth at a place where g = 9.80 m/s2 and 5320 N on the surface of another planet, what is the acceleration due to gravity on that planet?
63.3 m/s2
A cart with an initial velocity of 5.0 m/s to the right experiences a constant acceleration of 2.0 m/s2 to the right. What is the cart's displacement during the first 6.0 s of this motion?
66 m
What must be your average speed in order to travel 350 km in 5.15 h?
68.0 km/h
What is the mass of an object that experiences a gravitational force of 685 N near Earth's surface where g = 9.80 m/s2?
69.9 kg
A motorist travels 160 km at 80 km/h and 160 km at 100 km/h. What is the average speed of the motorist for this trip?
89 km/h
Which of the following quantities has units of a velocity? (There could be more than one correct choice.)
9.8 m/s downward -120 m/s
The components of vector are given as follows:Ax = +7.6Ay = -6.4The magnitude of is closest to:
9.9
A person has a weight of 200 lbs. That person has a mass of ? (kg) hint: 10N is 2.2 lbs weight(N) = mass (kg) x 10. (10 on earth) about
91 kg
A stone is thrown horizontally with an initial speed of 10 m/s from the edge of a cliff. A stopwatch measures the stone's trajectory time from the top of the cliff to the bottom to be 4.3 s. What is the height of the cliff if air resistance is negligibly small?
91 m
A stone is thrown horizontally with an initial speed of 10 m/s from the edge of a cliff. A stopwatch measures the stone's trajectory time from the top of the cliff to the bottom to be 4.3 s. What is the height of the cliff if air resistance is negligibly small? hint: ignore the fact that the stone wa thrown horizontally. Along the vertical, it is in free-fall and there is no initial velocity (along the veritcal). So its a free-fall problem. you are solving for the vertical displacement delta Y
91 m
An object is being acted upon by three forces and as a result moves with a constant velocity. One force is 60.0 N along the +x-axis, and the second is 75.0 N along the +y-axis. What is the magnitude of the third force?
96.0 N
The magnitude of is 5.5 m, and this vector lies in the second quadrant and makes an angle of 34° with the +y-axis. The components of are closest to
Ax = -3.1 m, Ay = 4.6 m.
Building on the previous questions. A and B are 2 forces pulling a crate. If you want the crate to stay at rest, you need to introduce another force C (pull). So the crate is in equilibrum. What is true.
C is along the negative x-axis
A ball is thrown straight up, reaches a maximum height, then falls to its initial height. Which of the following statements about the direction of the velocity and acceleration of the ball as it is going up is correct? hint: acceleration has the same direction as the force (weight)
Its velocity points upward and its acceleration points downward.
A small car meshes with a large truck in a head-on collision. Which of the following statements concerning the magnitude of the momentum change during the collision is correct? (There could be more than one correct choice.)
The small car and the truck experience the same magnitude momentum change.
A platform is rotating at a rate of 90 degrees / s. Its a uniform circular motion (obviously). What is true (the (linear) speed is (total distance)/time (m/s)
The speed of the fly is twice the speed of the lady bug
Starting from rest, a particle confined to move along astraight line is accelerated at a rate of 2 m/s2
The speed of the particle increases by 2 m/s during each second.
In an air-free chamber, a pebble is thrown horizontally, and at the same instant a second pebble is dropped from the same height. Compare the times of fall of the two pebbles.
They hit at the same time.
An object is moving with constant non-zero velocity in the +x direction. The velocity versus time graph of this object is
a horizontal straight line
An object is moving with constant non-zero acceleration in the +x direction. The position versus time graph of this object is
a parabolic curve.
In class, we discussed the experiments Galileo did using inclined plane. To measure time, he used
a pendulum
An object is moving with constant non-zero velocity in the +x direction. The position versus time graph of this object is
a straight line making an angle with the time axis.
A freely-falling watermelon falls with constant speed.
acceleration.
The slope of a velocity versus time graph gives
acceleration.
Human reaction time is usually greater than 0.10 s. If your friend holds a ruler between your fingers and releases it without warning, how far can you expect the ruler to fall before you catch it, assuming negligible air resistance?
at least 4.9 cm
If the position versus time graph of an object is a horizontal line, the object is
at rest.
Which one of the following is not a vector quantity?
average speed
Over the nine-second interval shown, we can say that the speed of the particle hint: before 3.5s , the velocity is negative so its moving to the left. But the magnitude of the velocity is decreasing. After 3.5 s, the velocity is positive. so its moving @ right. But the magnitude is increasing. So it reversed its direction.
decreases and then increases.
A postal truck driver driving due east gently steps on her brake as she approaches an intersection to reduce thespeed of the truck. What is the direction of the truck's acceleration, if any? (hint: the acceleration has the same direction as the force)
due west
The skater is moving along a number line. + is @right and - is @ left. What is true
his velocity is negative
For general projectile motion with no air resistance, the horizontal component of a projectile's acceleration
is always zero.
Here is the distance from the origin versus time of an object. And the kinematics equation
its speed is increasing, acceleration is constant
Which of the following quantities are units of momentum? (There could be more than one correct choice.)
kg ∙ m/s N ∙ s
A brick is resting on a rough incline as shown in the figure. The friction force acting on the brick, along the incline, is
less than the weight of the brick.
Twelve seconds after starting from rest, a freely-falling cantelope has a speed of
more than 100 m/s.
If the velocity versus time graph of an object is a horizontal line, the object is
moving with zero acceleration.
For general projectile motion with no air resistance, the horizontal component of a projectile's velocity
remains a non-zero constant.
What is true
the car is moving @ right and slowing down
Here is a box sliding on an inclined plane. The x-axis is along the plane. the y-axis is perpendicular to the plane. What is true?
the green vector is the normal force and the black vector the weight
You have a stack of bouncing ball and thrown them against the wall. one after another. you dont catch them. The thrust of the platform depends on (the net force acting on the platform)
the speed of the throw and the number of balls thrown per unit time
Here is the position (on the number line) on an object as a function of time hint: is the steepness of the line change?
ts velocity is constant
The slope of a position versus time graph gives
velocity.
