Physics Exam Prep
A man leans over the edge of a cliff and throws a rock upward at 4.9 m/s. Neglecting air resistance, two seconds later the rock's speed is:
14.7 m/s
A car starts at rest and accelerates as quickly as possible. If the acceleration is 1.2 m/s/s and the car accelerates for 10.0 seconds, what will the car's final velocity be?
12 m/s
Because the atmosphere is thinner at higher elevations, air resistance would also be less. Would you expect the terminal velocity at higher elevations to be greater, the same or less than it is at sea level?
Greater than at sea level
The velocity of a plane is reported as 100m/s and its acceleration is reported as -10m/s/s.
The plane is slowing down.
Disregarding air resistance, objects fall with constant
acceleration
A projectile launched from level ground hits a target on the ground 100 meters away from the launch site. If the projectile hits the target with a speed of 124 m/s what was the initial speed with which the projectile was fired?
124 m/s
A car accelerates from rest at 0.21 m/sec^2 for 2.0 minutes. What is its final velocity?
25 m/s
Vector A has a magnitude of 31.1 m at an angle of 60.0 degrees. Vector B has a magnitude of 11.4 m at an angle of 290.0 degrees. What is the sum of vector A and vector B?
25.4 m, 39.7 degrees
A girl pulls on a 10.0-kg wagon with a constant horizontal force of 30.0 N. If there are no other horizontal forces, what is the wagon's acceleration in meters per second per second?
3.00 m/s/s
Aimed at an angle of 45 degrees, a cannon has a range of 4,123 feet. What is the initial speed of a cannonball launched from this cannon? Assume the cannonballs land at the height from which they were launched.
3.6 x 10^2 ft/s
A car accelerates from rest for 5 seconds until it reaches a speed of 20m/s. What is the car's acceleration in meters per second per second?
4 m/s/s
A man leans over the edge of a cliff and throws a rock upward at 4.9 m/s. Neglecting air resistance, one second later the rock's speed is:
4.9 m/s
A driver is driving down the road and sees an elk in his headlights. The driver hits the brakes, which provide an acceleration of -7.0 m/sec^2. If the car's initial velocity was 25 m/sec, how far will the car skid before coming to a stop?
45 m
A 10-kilogram block with an initial velocity of 10 m/s slides 10 meters across a horizontal surface and comes to rest. It takes the block 2 seconds to stop. The stopping force acting on the block is about:
50 N
A rocket ship weighs 24,561 Newtons on earth. How much will it weigh on Jupiter? (The acceleration due to gravity on Jupiter is 23.2 m/s^2)
58,000 N
In an archery competition, an archer stands on a hill so that the arrow in her bow is 20.0 meters above the ground and is aimed at an angle of 0o relative to the ground. If the archer is trying to hit a target that lies on the ground 118 m away, with what initial velocity must she launch her arrow? (Note: the picture is not drawn to scale)
59 m/s
A block is dragged without acceleration in a straight-line path across a level surface by a force of 6N. What is the force of friction between the block and the surface?
6 N
A projectile is fired with a certain initial velocity from the surface of the earth. If the same projectile were taken to the moon and shot from the surface of the moon with the same initial velocity, would it have a larger, smaller, or identical range? Assume the projectile lands at the height from which it was launched.
On the moon it will have larger range
Arnold Strongman and Suzie Small each pull very hard on opposite ends of a massless rope in a tug-of-war. The greater force on the rope is exerted by:
both the same, interestingly enough
A player catches a ball. Consider the action force to be the impact of the ball against the player's glove. The reaction to this force is the:
force the glove exerts on the ball
If an object falling freely downward from rest were somehow equipped with an odometer to measure the distance it travels, then the amount of distance it travels in each succeeding second would be
greater than the previous second
In each second of fall, the distance a freely falling object will fall during that second is:
increasing
A bullet is dropped into a river from a very high bridge. At the same time, another bullet is fired from a gun, straight down towards the water. Neglecting air resistance, the acceleration just before striking the water:
is the same for each bullet
A kilogram is a measure of an object's
mass
A ball is thrown upwards and caught when it comes back down. Neglecting air resistance, its speed when caught is:
the same as the speed it had when thrown upwards
Roll a bowling ball off the edge of a table. As it falls, its horizontal component of velocity:
remains constant
Which of the following is NOT a vector quantity?
speed
An object weighs 30 N on Earth. A second object weighs 30 N on the moon. Which has the greater mass?
the one on the moon
The acceleration of a car is zero.
the velocity may or may not be zero.
With respect to this scenario: A bullet is shot out of a gun straight up in the air. When it falls back to earth, a radar gun measures its velocity to be 125 m/sec downwards when it reaches the same place from which it was fired. (Ignore any effects of air resistance.)-- When the bullet reached its maximum height, what was its acceleration?
-9.8 m/s/s (downward)
A karate chop delivers a blow of 3000 N to a board that breaks. The force that acts on the hand during this event is actually:
3000 N
If a rocket initially at rest accelerates at a rate of 50m/s^2 for one minute, its speed will be
3000m/s
A diver is on a hill overlooking a lake. If the hill is 45 feet above the surface of the water and the diver jumps horizontally (Q=0o) with an initial speed of 20.0 ft/s, how far from the hill will the diver hit the lake?
34 ft
At one instant an object in free fall is moving upward at 50 meters per second. One second later its speed is about:
40 m/s
A 1.0-kg mass at the earth's surface weighs:
9.8 N
If you drop an object, it will accelerate downward at a rate of 9.8 meters per second per second. If you instead throw it downwards, its acceleration after it leaves the hand (in the absence of air resistance) will be:
9.8 m/s^2
An airplane that flies at an airspeed of 100km/h with a 10 km/h tailwind travels at 110km/h relative to the ground. If it instead flies into a 10km/h headwind, its groundspeed is
90km/h
A boat travels for 4.0 hours at a constant velocity of 10.0 m/sec. How far does the boat travel? (1 hr = 3600 sec)
1.4 x 10^5 m
A tow truck exerts a force of 3.0 x 10^3 N on a car, accelerating it at 2.0 meters per second per second. What is the approximate mass of the car?
1.5 x 10^3 kg
A hiker travels 1.8 km with a heading of 150.0 degrees and then 3.2 km at a heading of 350.0 degrees. What is the hiker's final displacement relative to his starting point?
1.6 km, 12 degrees
A plane heads due north (theta = 90 degrees) at a speed of 200.0 km/h. The wind is blowing towards the southeast (315 degrees) at 15.0 km/h. What will be the actual velocity of the plane?
1.90 x 10^2 km/h at 86.8 degrees
The force of friction on a sliding object is 10 newtons. The applied force needed to maintain a constant velocity is:
10 N
A ball is thrown 125 meters upward and then falls the same distance back to Earth. Neglecting air resistance, its total time in the air is about:
10 seconds
Ten seconds after starting from rest, an object falling freely downward will have a speed of about
100 m/s
A baseball player bats a ball with a force of 1000 N. The ball exerts a reaction force:
1000 N
An archer lies on the ground and lets loose an arrow with an initial velocity of 112 ft/s at an angle of 40.0o. What is the maximum height that the arrow will reach?
81.0 ft
What is the difference between speed and velocity?
Speed is a scalar quantity while velocity is a vector quantity.
An object is propelled along a straight-line path by a force. If the net force were doubled, the object's acceleration would:
double
As an object freely falls downward from rest:
its velocity increases
Which of the following would NOT necessarily be true for an object in static rotational equilibrium?
the sum of all forces applied in a clockwise direction would equal the sum of all forces applied in a counterclockwise direction
A parabolic path will result when:
there is constant velocity in the x-component and constant acceleration in the y-component.
The y-component of a projectile's velocity is 12.1 m/s. When the projectile once again passes by the height from which it was launched, what is the y-component of its velocity?
-12.1 m/s
A 10-N block and a 1-N block lie on a horizontal frictionless table. To push them with equal accleration, we would have to push with:
10 times as much force on the heavier block
One half second after starting from rest, a freely-falling object will have a speed of about:
5 m/s
Someone standing at the edge of a cliff throws one ball straight up and another ball straight down at the same initial speed. Neglecting air resistance, the ball to hit the ground below the cliff with the greater speed will be:
neither--they will both hit with the same speed
When a rock thrown straight upwards gets to the exact top of its path, its
velocity is zero and its acceleration is about 10 m/s/s
Consider that a boat capable of a speed of 15 km/h is crossing a river, heading in a direction of 130.0 degrees. The river has a current of 2.1 km/h at a heading of 200.0 degrees. What are the x and y components for the current's velocity?
x= -2.0 km/h, y= -0.72 km/h
Consider that a boat capable of a speed of 15 km/h is crossing a river, heading in a direction of 130.0 degrees. The river has a current of 2.1 km/h at a heading of 200.0 degrees. What are the x and y components of the boat's velocity (ignoring the current)?
x= -9.6 km/h, y= 11 km/h
The force required to maintain an object at a constant velocity in free space is equal to:
zero
The average speed of a horse that gallops a distance of 10 kilometers in a time of 30 minutes is
20km/h
With respect to this scenario: A bullet is shot out of a gun straight up in the air. When it falls back to earth, a radar gun measures its velocity to be 125 m/sec downwards when it reaches the same place from which it was fired. (Ignore any effects of air resistance.)-- When the bullet reached its maximum height, what was its velocity?
0 m/s
A bullet is fired at a target which is at the same height as the gun from which the bullet was fired. If the bullet takes 0.66 seconds to hit the target, how long did it take for the bullet to reach its maximum height?
0.33 s
What is the acceleration of a car that maintains a constant velocity of 100km/h for 10 seconds?
0m/s/s
The mass of a pet turtle that weighs 10 N is about:
1 kg
If a projectile is fired straight up at a speed of 10 m/s, the time it takes to reach the top of its path is about:
1 second
The vertical height attained by a basketball player who achieves a hang time of a full 1 second is about:
1.2 m
With respect to this scenario: A bullet is shot out of a gun straight up in the air. When it falls back to earth, a radar gun measures its velocity to be 125 m/sec downwards when it reaches the same place from which it was fired. (Ignore any effects of air resistance.)-- What was the velocity of the bullet when it left the gun?
125 m/s
Consider that a boat capable of a speed of 15 km/h is crossing a river, heading in a direction of 130.0 degrees. The river has a current of 2.1 km/h at a heading of 200.0 degrees. The magnitude and direction for the resultant final velocity of the boat is:
15 km/h at 139 degrees - add that 180 degrees!
A car accelerates at 2 meters per second per second. Assuming the car starts from rest, how much time does it need to accelerate to a speed of 30m/s?
15 seconds
At one instant an object in free fall is moving downward at 50 meters per second. One second later its speed is about:
60 m/s
A mechanic unscrews a nut with a 15-cm wrench. If he grasps the wrench at the end and applies a 456 N force perpendicular to the wrench, how much torque is he applying to the nut?
68 N-m
If a car increases its velocity from zero to 60km/h in 10 seconds, its acceleration is
6km/h/s
A car accelerates from rest at 2 meters per second per second. What is its speed 3 seconds after the car starts moving?
6m/s
A bullet is fired straight down from the top of a high cliff. Neglecting air resistance, the acceleration of the bullet in meters per second per second is:
9.8 m/s/s
Suppose one used the range equation to calculate the range of a projectile. Now another calculation is made but this time the effect of air resistance is included. Would the newly calculated range be the same, less, or greater than the initial calculation? Assume the impact height is the same as the launch height.
With air resistance, the range would be less.
It takes 6 seconds for a stone to fall to the bottom of a mine shaft. How deep is the shaft?
about 180 m
A package falls off a truck that is moving at 30 m/s. Neglecting air resistance, the horizontal speed of the package just before it hits the ground is:
about 30 m/s
A ball is thrown upwards. Neglecting air resistance, what initial upward speed does the ball need to remain in the air for a total time of 10 seconds?
about 50 m/s
If the mass of an object does not change, a constant net force on the object produces constant:
acceleration
An object travels 8 meters in the first second of travel, 8 meters again during the second second of travel, and 8 meters again during the third second. Its acceleration in meters per second per second is:
constant velocity=0
An object that moves with constant velocity is in a state of:
dynamic translational equilibrium.
As a ball falls, the action force is the pull of the Earth's mass on the ball. The reaction force is the:
pull of the ball's mass on the Earth
A rock is thrown upward at 50 degrees with respect to the horizontal. As it rises, its horizontal component of velocity
remains unchanged
Suppose you throw a Frisbee in the air towards your friend. It spins at a constant rate, but the speed at which it moves towards your friend is changing due to the wind. The Frisbee is in a state of:
rotational equilibrium
A mover pushes a piano having a mass of 650 kg across a cement driveway (coefficient of static friction = 0.42, coefficient of kinetic friction = 0.24). Assuming that the mover has already got the piano started moving, how much force is required to keep the piano moving at a constant velocity?
1500 N
A person is pushing on a 567-Newton statue. What frictional force must be overcome to get the statue moving? (coefficient of static friction = 0.32, coefficient of kinetic friction= 0.20)
180 N
Two plumbers are working at a site. The first tries to unscrew a pipe with a wrench and cannot budge it. The second one is twice as strong as the first one but his wrench is twice as long. What is the ratio of the torque exerted by the first plumber as compared to the second plumber (torque of first plumber : torque of second plumber)?
1:4
If a projectile is fired straight up at a speed of 10 m/s, the total time to return to its starting position is about:
2 seconds
Consider that the velocity vector of a bicycle has an x-component of 1.7 m/sec and a y-component of -1.1 m/sec. What is the magnitude of the velocity vector and the direction of the bicycle?
2.0 m/s magnitude and -33 degrees direction
A car is traveling down a one-lane country road at 21 miles/hour. Up ahead, a truck is traveling the opposite direction at 15 miles/hour. If they are 0.20 miles apart, how long will it be before they run into each other, assuming neither one of them slows down?
20 seconds
A physicist measures the instantaneous velocity of an object in three different places along its journey. The velocities were 2m/sec, 4m/sec, and 8m/sec. She then measures the object's average velocity throughout the journey. Which of the following would be a reasonable average velocity?
3 m/sec
Ten seconds after starting from rest a car is moving at 40 m/s. What is the car's acceleration in meters per second per second?
40/10 = 4 m/s/s
A person is attracted toward the center of the Earth by a 4500-N gravitational force. The force of attraction of the Earth toward the person is:
4500 N
Suppose you are doing physics experiments outside in a thick fog. Fog makes the molecules and atoms in the air more difficult to move. In those circumstances, would you expect the air resistance in your experiments to be more, less or the same as it would be without fog?
Air resistance would be greater in fog
If you double the initial speed of a projectile launched upwards at an angle, what happens to that projectile's range? Assume that the projectile lands at the height from which it was launched.
Doubling the initial speed quadruples (4x) the range
Why graphically add and subtract vectors when we can analytically add and subtract them?
Graphically adding and subtracting vectors helps us to better visualize the situation.
A truck is moving at constant velocity. Inside the storage compartment, a rock is dropped from the midpoint of the ceiling and strikes the floor below. Ignoring air resistance, the rock hits the floor:
exactly below the midpoint of the ceiling.
A bicyclist is traveling at high speed and is not watching where he is going. His front tire catches in a sewer grating, causing the bike to stop almost instantly. This makes the rider fall off of the bicycle:
in front of the bike
A hunter on level ground fires a bullet at an angle of 10 degrees above the horizontal while simultaneously dropping another bullet from the level of the rifle. Which bullet will hit the ground first?
the dropped one
A stone is thrown horizontally from the top of a cliff. One second after it has left your hand its vertical distance below the top of the cliff is about:
y = 4.9t^2 with g = 9.8. With t = 1 s, then y = 4.9 which is about 5.0 m