Name: _________________________
Some Forceful Questions!
1
Definitions:
Force – a push or pull
Balanced forces – do not cause change in motion of an object.
Unbalanced forces – cause change in motion of n object.
Formulas:
Units:
Force = mass * acceleration (F = m*a)
Newton (N)
Math Example:
A ball with a mass of 2kg rolls across the street at an acceleration rate of 5 m/s2. With what force
will it hit the curb on the other side?
Identify
Variables
F=?
m = 2 kg
a = 5 m/s2
Identify
Formula
Show Work
F = m*a
F = m*a
Answer
(remember the units)
F=2*5
F = 10
10 N
Math Practice:
1. If a 2000 kg truck crashes into a tree at an acceleration rate of 4 m/s2, with how much force
did it hit the tree?
Variables
Formula
Show Work
Answer
F=
m=
a=
2. Patty has been lifting weights for three years. She wants to bench press 85 kg. If she has to
accelerate the weights at 0.25 m/s2, what is the force she needs to lift the 85 kg?
Variables
Formula
Show Work
Answer
Some Forceful Questions!
2
More Math Practice:
3. The police get to an accident scene and see two smashed cars. The investigator has
determined that the Ford truck was traveling at an acceleration rate of 23 m/s 2 and the books
say the trucks mass is 4800kg. With what force did the Ford truck hit the other car?
Variables
Formula
Show Work
Answer
4. While rollerblading, Cody was able to achieve an acceleration rate of 2 m/s2. If Cody has a
mass of 75kg, how much force did he have to use?
Variables
Formula
Show Work
Answer
5. A 10kg bowling ball would require what force to accelerate it down an alleyway at a rate of 3
m/s2?
Variables
Formula
Show Work
Answer
6. With what force will George St. Pierre hit BJ Penn if George has a mass of 77kg and
accelerates his fist at a rate of 2 m/s2?
Variables
Formula
Show Work
Answer
Some Forceful Questions!
3
But what if you know the force and need mass or acceleration?
If force = mass x acceleration then
F=m*a
mass = force / acceleration
m=F/a
and
acceleration = force / mass
a=F/m
Examples:
What is the mass of a falling rock if it hits the ground with a force of 147 newtons? Remember
that falling is acceleration due to gravity, 9.8 m/s2.
Indentify
Variables
Indentify
Formula
Show Work
F = 147N
m=?
a = 9.8 m/s2
m=F/a
m=F/a
Answer
(unit comes from
speed unit)
m = 147 / 9.8
m = 15
15 kg
What is the acceleration of a softball if it has a mass of 0.5 kg and hits the catcher’s glove with a
force of 25 newtons?
Variables
F = 25N
m = 0.5kg
a=?
Formula
Show Work
a = F/m
a=F/m
Answer
a = 25 / 0.5
a = 50
50 m/s2
Math Practice:
1. A baseball player used 37 newtons of force to hit a baseball with a mass of 0.28kg out of the
park. What was the baseball’s acceleration rate?
Variables
Formula
Show Work
Answer
2. What is the mass of a truck if it is accelerating at a rate of 5 m/s2 and hits a parked car with a
force of 14,000 newtons?
Variables
Formula
Show Work
Answer