Download Forces Review Worksheet

Forces Review Worksheet
1. Draw Free body diagrams for the following situations:
a. A beam hanging from a crane. (Hint: 2 Forces)
b. Your car when you press the gas pedal. (Hint: Net Force > 0)
c. A skydiver falling at constant velocity.
d. A kid sliding on a slip’n slide (Hint: They’re slowing down!)
2. Fill in the blank:
a. Inertia is a property of __________.
b. Weight is measured in ________. (Hint. It’s not kilograms!)
c. The symbol for the coefficient of friction is ______.
d. “SOH” stands for _______ = ___________ / ___________.
3. Write Newton’s Laws (check out the class notes):
a. Newton’s First Law:
b. Newton’s Second Law:
c. Newton’s Third Law:
4. Newton’s First Law Questions.
a. What must you increase if you want to increase your inertia?
b. What is the net force acting on an object moving at a constant velocity?
5. Newton’s Second Law Questions. (MATH)
a. An object has a mass of 600 kg. What is the net force if it accelerates at 7 m/s 2 ?
b. An object with a net force of 200 N has a mass of 25 kg. What is it’s acceleration?
c. In Newton’s Second Law, mass and acceleration are __________ proportional, while force
and acceleration are ___________ proportional.
6. Newton’s Third Law Questions.
a. Newton’s Cradle shows an example of forces that are ________ in magnitude and
_________ in direction.
b. If you apply a force of 10 N to the ground, what is the force applied back to you?
7. Force of Gravity Calculations
a. A textbook has a mass of 4 kg. What is it’s weight?
b. A hovercraft has a mass of 75 kg. How much force is required to keep it off the ground?
c. A whale is stuck on the beach! It has a mass of 90,000 kg. What is the normal force acting on
the whale?
d. What is the weight of an asteroid in space with a mass of 6,000 kg? What is the weight of the
same asteroid if it lands on the moon? (acceleration due to gravity on the moon is (1.6 m/s2
8. Friction Calculations (What is the equation for friction?)
a. Your car is moving at a constant velocity. It weighs 10,000 N. If the friction between your car
and the road is .25, what is the force of friction?
b. The force of friction of a soccer ball on a field is 2.7 N. If the normal force on the ball is 9N,
what is the coefficient of friction between the ball and the field?
c. A force of 70 N is applied to a wooden block to keep it moving at a constant velocity. What is
the force of friction acting on the block? (Hint: Think about your Net Force)
9. Component Forces.
a. A force of 60 N is applied at a 30 degree angle to the ground. What is the vertical component
of this force? (hint: remember your answer to question 2d.)
b. A metal ball impacts a cup at a 75 degree angle with a force of 15 N. What is the horizontal
force applied to the cup? (hint: draw your triangle, are you working with “SOH” or “CAH”?)
10. Challenge Question
A smart car crashes into a wall! In 2 seconds, its velocity drops from 60 m/s to 0 m/s. If the car
has a mass of 750 kg, what was the force it applied to the wall?