physics final exam conceptual
two objects are thrown from the top of a tall building and experience no appreciable air resistance. One is thrown up, and the other is thrown down, both with the same initial speed. What are their speeds when they hit the street?
they are traveling at the same speed
when you ride a bicycle, in what direction is the angular velocity of the wheels?
to your left
A 4.0-kg object is moving with speed 2.0 m/s. A 1.0-kg object is moving with speed 4.0 m/s. Both objects encounter the same constant braking force, and are brought to rest. Which object travels the greater distance before stopping?
both objects travel the same distance
as you are leaving a building, the door opens outward. If the hinges on the door are on your right, what is the direction of the angular velocity of the door as you open it?
down
you swing a bat and hit a heavy box with a force of 1500 N. the force the box exerts on the bat is....
exactly 1500 N whether or not the box moves
if the acceleration of an object is negative, the object must be slowing down (t or f)
false
suppose that a car traveling to the west (-x direction) begins to slow down as it approaches a traffic light. which statement concerning its acceleration in the x direction is correct?
its acceleration is positive but its velocity is negative
a brick is resting on a rough incline. the friction force acting on the brick along the incline is...
less than the weight of the brick
A ball drops some distance and gains 30 J of kinetic energy. Do NOT ignore air resistance. How much gravitational potential energy did the ball lose?
more than 30 J
a ball is thrown directly upward and experiences no air resistance. Which one of the following statements about its motion is correct?
the acceleration is downward during the entire time the ball is in the air
a ball is tossed vertically upward. when it reaches its highest point (before falling back downward)
the velocity is zero, the acceleration is directed downward, and the force of gravity acting on the ball is directed downward
a box slides down a frictionless plane inclined at an angle above the horizontal. the gravitational force on the box is directed...
vertically
is it possible for a system to have negative potential energy?
yes, since the choice of the zero of potential energy is arbitrary
a stalled car is being pushed up a hill at a constant velocity by three people. the net force on the car is....
zero
Two stones, one of mass m and the other of mass 2 m , are thrown directly upward with the same velocity at the same time from ground level and feel no air resistance. Which statement about these stones is true?
At its highest point, the heavier stone will have twice as much gravitational potential energy as the lighter one because it is twice as heavy
)Two identical balls are thrown directly upward, ball A at speed v and ball B at speed 2 v , and they feel no air resistance. Which statement about these balls is correct?
Ball B will go four times as high as ball A because it had four times the initial kinetic energy
Block 1 and block 2 have the same mass, m , and are released from the top of two inclined planes of the same height making 30° and 60° angles with the horizontal direction, respectively. If the coefficient of friction is the same in both cases, which of the blocks is going faster when it reaches the bottom of its respective incline?
Block 2 is faster
In a collision between two objects having unequal masses, how does magnitude of the impulse imparted to the lighter object by the heavier one compare with the magnitude of the impulse imparted to the heavier object by the lighter one?
Both objects revceive the same impulse
an object is moving to the right and experiencing a net force that is directed to the right. the magnitude of the force is decreasing with time. the speed of the object is....
increasing
Jack and George meet in the middle of a lake while paddling in their canoes. They come to a complete stop and talk for a while. When they are ready to leave, Jack pushes George's canoe with a force F to separate the two canoes. What is correct to say about the final momentum and kinetic energy of the system if we can neglect any resistance due to the water?
the final momentum is zero but the final kinetic energy is positive
a 20 ton truck collides with a 1500 lb car and causes a lot of damage to the car. during the collision...
the force of on the truck due to the collision is exactly equal to the force on the car
Consider two less-than-desirable options. In the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. In the second option you are driving 30 mph and crash head-on into a stationary brick wall. In neither case does your car bounce off the thing it hits, and the collision time is the same in both cases. Which of these two situations would result in the greatest impact force?
the force would be the same in both cases
Two objects, one of mass m and the other of mass 2 m , are dropped from the top of a building. When they hit the ground
the heavier one will have twice the kinetic energy of the lighter one
A 1.0-kg block and a 2.0-kg block are pressed together on a horizontal frictionless surface with a compressed very light spring between them. They are not attached to the spring. After they are released and have both moved free of the spring
the lighter block will have more kinetic energy than the heavier block
A box of mass m is pressed against (but is not attached to) an ideal spring of force constant k and negligible mass, compressing the spring a distance x . After it is released, the box slides up a frictionless incline as shown in the figure and eventually stops. If we repeat this experiment with a box of mass 2 m
the lighter box will go twice as high up the incline as the heavier box
in an INELASTIC collision between two objects....
the momentum of the system is conserved but the kinetic energy of the system is not conserved