5.
A 900. kg truck’s engine applies a force of 200. N to accelerate it
rightward. The truck experiences a 600. N frictional force.
a. Draw the free-body diagram to the right.
Ff = 600. N
b. Calculate the net force on the truck. Include direction.

Fn = 8820 N
Fa = 200. N
Truck
Fg = 8820 N
Fnet = Ff – Fa = 600. N – 200. N = 400. N left
c. Use Newton’s 2nd law to calculate the acceleration of the
truck.
ma a
6.
m
00. N
900. kg
A pitcher throws a 0.145 kg baseball to the right with 150. N of
force.
a. Draw the free-body diagram to the right.
Fn = 1.42 N
Baseball
b. Calculate the net force on the ball. Include direction.
Fa = 150. N
Fg = 1.42 N
Fnet = 150. N right
c. Use Newton’s 2nd law to calculate the acceleration of the
ball.
ma a
7.
m
0. N
0.
kg
The driver of a power wheels car (total mass = 45 kg), moving at
1.5 m/s to the left, applies a 25 N braking force.
a. Draw the free-body diagram to the right.
b. Calculate the net force on the car. Include direction.
Fnet = 25 N right
c. What will happen to the car’s motion? Be specific.

The car will slow decelerate until it stops.
Fn = 441 N
Car
Fa = 25 N
Fg = 441 N