Download Class Set: Use your own paper! Forces and Laws of Motion A 80

Class Set: Use your own
paper!
Forces and Laws of Motion
1. A 80-kilogram skydiver is falling at a constant speed near the surface of Earth. The magnitude of the force
of air friction acting on the skydiver is approximately
2.
A 2.5-kilogram lab cart is accelerated uniformly from rest to a speed of 2.0 meters per second in 0.50
second. What is the magnitude of the force producing this acceleration?
3.
Which person has the greatest inertia?
a 110-kg wrestler resting on a mat
or
a 50-kg girl sprinting at 10 m/s
4. Which object has the most inertia?
a 0.1-kilogram baseball traveling at 20 meters per second
a 5-kilogram bowling ball traveling at 3 meters per second
or
5. A box is pushed toward the right across a classroom floor. The force of friction on the box is directed
toward which direction?
6. A 60-kilogram mass is moving across a horizontal surface at 5.0 meters per second. What is the magnitude
of the net force required to bring the mass to a stop in 8.0 seconds?
7. The acceleration due to gravity on the surface of planet X is 19.6 meters per second2. If an object on the
surface of this planet weighs 98 newtons, the mass of the object is
8. Two carts are pushed apart by an expanding spring, as shown in the diagram below. If the average force on
the 1-kilogram cart is 10 Newtons, what is the average force on the 2-kilogram cart?
9. A 2.0-kilogram laboratory cart is sliding across a horizontal frictionless surface at a constant velocity of 4.0
meters per second east. What will be the cart’s velocity after a 6.0-newton westward force acts on it for 2.0
seconds?
10. A 0.15-kilogram baseball moving at 20 meters per second is stopped by a catcher in 0.010 second. The
average force stopping the ball is
11. The diagram on the next page shows a horizontal 12-newton force being applied to two blocks, A and B,
initially at rest on a horizontal, frictionless surface. Block A has a mass of 1.0 kilogram and block B has a
mass of 2.0 kilograms. What is the acceleration of Block B?
Use the following statements to answer questions 14 to 16
A person riding in the back of a pickup truck traveling at 70 km/h on a straight, level road throws a ball with a
speed of 15 km/h relative to the truck in the direction opposite to the tuck’s motion. One observer is stationary
on the side of the road and another observer is traveling in a car that is moving in the same direction as the truck
but passing the truck at a faster speed.
12. What is the velocity of the ball relative to a stationary observer by the side of the road?
13. What is the velocity of the ball relative to the driver of a car moving in the same direction as the tuck at a
speed of 90 km/h?
14. Describe how the velocity of the ball would appear to be traveling for the observer in the car as compared
to the direction of the truck
The same direction as the truck or
The opposite direction as the truck
15. Three forces act on a box on an inclined plane as shown in the diagram below. [Vectors are not drawn to
scale.] If the box is at rest, what is the net force acting on the box?
16. The diagram below shows a sled and rider sliding down a snow-covered hill that makes an angle of 30° with
the horizontal.
Draw the vector that best represents the direction of the normal force, FN, exerted by the hill on the sled?
17. Draw a vector free-body diagram best represents a cart slowing down as it travels to the right on a
horizontal surface?
18. The diagram below shows a 4.0-kilogram object accelerating at 10. meters per second2 on a rough
horizontal surface. What is the magnitude of the frictional force Ff acting on the object?