Download Intro to Physics - Fort Thomas Independent Schools

Intro to Physics
Starter 6—Problem Set for Newton’s Laws
Name __________
Convert by Factor-Label Method
1.
55 g into mg.
2.
66 km/hr into m/s
Calculate using weight equation
w = mg
g = 9.8 m/s2
1.
gmoon = 1.6 m/s2
A rock weighs 88 N on Earth. How much mass does it have?
2.
What is the weight of a 449 kg cart on Earth? What is the difference in weight if it was
on the Moon?
Calculate using 2nd Law of Motion
F = ma
a = Vf – Vi
t
1.
What is the net force that causes a 2.4 kg wheelbarrow to accelerate at a rate of 2.4
m/s2?
2.
What is the rate of acceleration of a 4560 kg dump truck that uses 1299 N of braking
force to slow down?
3.
What is the mass of a cart that accelerates at a rate of 5.6 m/s2 when it receives an
accelerating force of 301 N?
4.
A 45 kg scooter speeds up from 4.0 m/s to 12 m/s in 6.7 seconds. What is the force
causing the acceleration of the scooter? (hint: you must first solve for the missing
variable)
5.
A bicyclist/bicycle has a combined mass of 75 kg and is accelerating at a rate of 3.1
m/s2. If the force of friction and air resistance acting on the bicyclist equals 21 N,
what is the applied force acting on the bicyclist?
4400 N
Starter 7
Using Factor-label method, convert:
 812 m/s into km/hr
812 m x 1 km x 60 s x 60 min = 2923.2 km/hr
s 1000 m 1 min
1 hr
 0.31 km into cm
0.31 km x 1000 m x 100 cm = 31,000 cm
1 km
1m
Starter 8
Using Factor-Label Method, convert 24,009 cm into km.
1 km = 1000 m
1 m = 100 cm
24,009 cm x 1 m x 1 km
100 cm 1000 m
= 0.24009 km
Starter 9
Write each of Newton's Three laws of motion in your spiral notebook. Leave space beneath
each for your explanation.
Explain how each law applies to the crash test video
1st Law: law of inertia
– The barrier applied an unbalanced force to the car, which quickly changed the
velocity of the car.
– Crash Test Dummies continued to move forward after the collision due to inertia
until receiving an unbalanced force.
– The seat belts (and steering wheel) provided the unbalanced force for the Crash
Test Dummies
2nd Law Fnet = ma or accel of object depends on Fnet/mass
• A large net force produces a large acceleration
• You can calculate the force of the crash if you know mass and acceleration of the car.
3rd Law For every action force there is an equal and opposite action force
• The action force is the car hitting the wall, reaction force is the wall hitting the car
(Action and reaction forces are equal and opposite) the car hit the wall with the same
force that the wall hit the car, which was enough to crush the front end of the car.