Free Body Diagrams For each situation, draw a free body ... - the Vault

Name: ______________________________
Date: ______________________________
Section C D F
Free Body Diagrams
Mr. Alex Rawson
Physics
For each situation, draw a free body diagram depicting every force acting upon
the object. Clearly note both what each force is and the direction of each force.

Name: ______________________________
Date: ______________________________
Section C D F
Forces I
1. What net external force is required to push a 45 kg suitcase with an acceleration of 3.5 m/s 2 to the right?
Draw a free-body diagram of the suitcase.
2. What acceleration will you give to a 60 kg box if you push it with a force of 147 N?
3. An 1520 kg car is moving to the right at a constant velocity of 5.94 m/s.
a. What is the net force on the car?
b. What would be the net force on the car if it were moving to the left?
Mr. Alex Rawson
Physics
4. A freight train has a mass of 4.5 10 7 kg. If the locomotive can exert a constant pull of 10.5 10 5 N, how
long would it take to increase the speed of the train from rest to 85 km/h?

5. A 32 kg mass starts from rest and slides down an inclined plane 8.0 10 -1 m long in 0.8 s. What net
force is acting on the mass along the incline?
6. A 1350 kg car is pulling a 475 kg trailer. Together, the car and trailer have an acceleration of 2.15 m/s 2
directly forward.
a. Determine the net force on the car.
b. Determine the net force on the trailer.

Name: ______________________________
Date: ______________________________
Section C D F
Forces II
1. A 5 kg object lies at rest on a bench. If the bench were to be lifted, slowly, how would the normal force
and static friction force change as the angle of inclination increased? Draw Free Body Diagrams for the
situations below, label forces, axes, Fnet,x , Fnet,y , and calculate FN and Fs for each.
a. = 0
b. = 10
c. = 30
d. = 45
Fnet,x =
Fnet,y =
Fnet,x =
Fnet,y =
Fnet,x =
Fnet,y =
Fnet,x =
Fnet,y =
Mr. Alex Rawson
Physics
FN, = 0 =
Fs, = 0 =
FN, = 10 =
Fs, = 10 =
FN, = 30 =
Fs, = 30 =
FN, = 45 =
Fs, = 45 =

2. Two lifeguards pull on ropes attached to a raft. If they pull in the same direction, the raft experiences a
net external force of 300 N to the right. If they pull in opposite directions, the raft experiences a net
external force of 135 N to the left.
a. Draw a free-body diagram representing the raft for each situation. This includes the forces, Fnet,x
and Fnet,y
b. Find the force exerted by each lifeguard on the raft. (Disregard any other forces acting on the
raft.)
3. A 5 kg bucket of water is raised from a well by a rope. If the upward acceleration of the bucket is 1.2
m/s 2 , find the force exerted by the rope on the bucket of water.
4. A boat moves through the water with a 2.9 10 3 N forward push by the motor, and a kinetic friction
force caused by the water of 1.9 10 3 N.
a. What is the acceleration of the 1200 kg boat?
b. If it starts from rest, how far will it move in 3 s?
c. What will its velocity be at the end of this time interval?

Name: ______________________________
Date: ______________________________
Section C D F
Forces III
1. A 52 kg person escapes from a burning building by jumping from a window 35 m above a catching net.
Assuming that air resistance exerts a 95 N force on the person during the fall, determine the person's
velocity just before hitting the net.
2. If the left cable is inclined at an angle 37 o above the horizontal, find the force exerted by each cable to
support the 800 N bag in Figure 4-32.
3. A 94 kg clock is initially at rest on a horizontal floor.
a. If it takes a 656 N horizontal force to set it in motion, find µs.
4.
Mr. Alex Rawson
Physics
b. After the clock is in motion, if a horizontal force of 555 N keeps it moving with a constant speed,
find µk.

A 3.50 kg block starts from rest at the top of a 30.0° incline and slides 2.60 m down the incline in 1.50 s.
a. Find the acceleration of the block.
b. Find the coefficient of kinetic friction between the block and the incline.
c. Find the frictional force acting on the block.
d. Find the speed of the block after it has slid a distance of 2.60 m.
5. The coefficient of static friction between the 22 kg crate and the 35.0° incline of Figure 4-34 is 0.1.
What is the minimum force, F, that must be applied to the crate perpendicular to the incline to prevent
the crate from sliding down the incline?