C165-Module 4: Friction Gravity & Momentum Quiz
The law of conservation of total linear momentum states that __________. The total momentum in a system is different before and after a collision. Any momentum lost by one object in a collision will be gained by the other. The momentum of any object involved in a collision does not change. The type of collision determines whether or not the total momentum is conserved.
Any momentum lost by one object in a collision will be gained by the other.
Why is an applied force necessary to keep most objects in our world moving at a constant velocity? Because a force is needed to accelerate an object Because a frictional force opposing motion acts on most objects Because the object's weight acts to slow it down Because the natural tendency of any object is to come to rest
Because a frictional force opposing motion acts on most objects
Which of the following is a disadvantage of friction? Air resistance of a parachute slows down the descent of a skydiver. Friction reduces the efficiency of engines and other machines by converting parts of their kinetic energy into heat. Friction makes it possible for you to grasp items with your hand. Friction enables you to walk.
Friction reduces the efficiency of engines and other machines by converting parts of their kinetic energy into heat.
If we could stop a planet for just an instant and then let it go, what would happen to it? It would spiral away from the sun into space. It would remain motionless. It would fall into the sun. It would continue orbiting the sun.
It would fall into the sun.
Which of the following statements is inaccurate about gravity? Only very large objects exert a gravitational force. Gravity is an attractive force. It would be impossible to walk without gravity. The force of gravity is what holds us to Earth's surface.
Only very large objects exert a gravitational force.
Consider a box lying on a table. If another box is stacked on top of it, how will the gravitational force (weight) of the top box affect the frictional force between the bottom box and the table if someone pushes slowly on the lower box? The frictional force will increase. It is impossible to determine how the frictional force will change. The frictional force will decrease. The frictional force will remain the same.
The frictional force will increase.
If the distance between Earth and sun were decreased, how would the gravitational force between them change? The gravitational force would remain the same. The gravitational force would decrease. The gravitational force would increase.
The gravitational force would increase.
A brick is dragged across a concrete floor. The type of friction that acts between the brick and the floor is ________ friction. static rolling fluid kinetic
kinetic
If the mass of an object is halved and its speed doubled, its momentum will __________. not change halve double increase by a factor of 4
not change
Which of the following factors has no effect on the force of friction between two solid objects? the type of materials the objects are made of the smoothness of the surfaces between the objects the contact force between the objects the relative speed of the objects to each other
not type
If the mass of the Earth were doubled (while keeping its size the same), how much more would you weigh at the surface? You would weigh half as much. You would weigh four times as much. You would weigh the same. You would weigh twice as much.
you would weight twice as much
Friction is a force that usually slows down or prevents motion. However, friction can sometimes cause an object to speed up, such as when you walk forward. The frictional force between the ground and your foot is what actually pushes you forward (as your foot pushes backward on the ground). Identify which instance below describes a scenario in which the frictional force causes the object it acts upon to speed up rather than slow down. A package on a moving conveyer belt A sled on snow Sliding a book across your desk Air resistance on a moving car
A package on a moving conveyer belt
