Physics Review

1) Write Newton’s 1st Law. Give an example.

An object in motion stays in motion…An object at rest remains at rest….Unless acted upon by an unbalanced force!

For example, when you slam on the breaks of a car, stuff flings forwardoff the seat (because it was in motion and remains so…)

2) Write Newton’s 2nd Law. Give an example.

F = ma

It is easier to push a VW beetle than a Chevrolet Suburban…

A bullet hurts more that is shot than thrown at you!

3) Write Newton’s 3rd Law. Give an example.

examples include:

a rocket shoots “stuff” down and goes up

Recoil: a bullet moves forward asthe gun pushes back into your shoulder

For every action there is an equal and opposite reaction

4) Explain how force, mass, and acceleration are related. Not just the formula.

If force is held the same…when mass is increased, acceleration

will decreased.

If mass is the same, it takes greaterforce to obtain greater acceleration

If acceleration held the same, a largermass requires a larger force

F = ma

5) Draw a graph for the following scenarios: A) A person running fastB) A person walking C) A person that is standing stillD) A person running that stops for a water break.

runn

ing

walking standing still

6) Explain the speed graph. A. Who ran fastest? Albert; he got to 100 meter first!

Slowest? Charlie; he took the longest to get to 10 meters

6) Explain the speed graph. B. Who stopped (and at what time)?

Charlie stopped from 8 to 13 seconds

6) Explain the speed graph to the right.

C. How fast was Charlie going in the first eight seconds?

s = d/t s = 50m / 8 sec s = 6.25 m/s

6) Explain the speed graph to the right. D. Who made it to the 20m point first?

Charlie; he was there in about 3 seconds!

E. How far was the race? 100 meters

7) Draw and label a picture of balanced forces.

20N 20N

8) Draw and label a picture of unbalanced forces.

20N 16N

20N 20N

or even….

9) Rudy watches a storm cloud on a weather map.The storm cell moved 15 Km in half an hour. What is

The storm’s speed in Km/hr?

s= d/tDistance (d) = 15Km

Time (t) = .5 hr (half an hour!)

s=d/t s = 15Km/.5hr

s= 30Km/hr

Answer: s = 30 Km/hr

10) Jennifer is driving her Lamborghini on I-45 heading north. She drove 112 Km to Huntsville in

1.3 hrs. What is Jennifer’s speed in Km/hr?

s= d/tDistance (d) = 112Km

Time (t) = 1.3 hr

s=d/t s = 112Km/1.3hr s = 86.15Km/hr

Answer: s = 86.15 Km/hr

11) For a science experiment, Julia rolls a metal ball down a 1 meter ramp. The ball takes .26 seconds to go down the ramp. What is the ball’s speed in m/s?

s= d/tDistance (d) = 1m

Time (t) = .26 s

s=d/t S = 1m/.26sec

s= 3.85m/s

Answer: s = 3.85 m/s

12) What is acceleration? What causes an object to accelerate?

acceleration is a change in velocity. It includes:• speeding up• slowing down• changing direction

acceleration is caused by unbalanced forces

13) Matthew lifts a 4.4Kg weight over his headwith an acceleration of 1.8m/s2. How much force

is Matthew exerting on the weights?

F = mamass (m) = 4.4 Kg

acceleration (a) = 1.8 m/s2

F=maF = 4.4Kg x 1.8 m/s2

F = 7.92 kg*m/s2

Answer: F = 7.92 N

14) Seth pushes a 33Kg cart with school suppliesacross the floor by accelerating it at a rate of 2.2m/s2.

How much force was applied to the cart.

F = mamass (m) = 33 Kg

acceleration (a) = 2.2 m/s2

F=ma F = 33Kg x 2.2 m/s2

F = 72.6 kg*m/s2

Answer: F = 72.6 N

15) A net force of 300 N causes a 30 kg cart to accelerate. At what rate will the cart accelerate?

a = F/mForce (F) = 300Nm (mass) = 30kg

a = F/m a = 300 N 30kg

a = 300 kg*m/s2 30 kg

Answer a = 10 m/s2

Convert the Newton!

16) What is velocity?

Speed with direction

for example: 68 miles per hour north

or

28 m/s down the ramp

17) What is potential energy?

Stored energy. Energy that has the ability to “do work.”

examples include •a rollercoaster at the top of a hill….

•a battery (chemical potential energy)

• the stress built up in a fault betweentwo of Earth’s plates.

18) What is kinetic energy?

Energy of motion…..

Examples include: •an apple falling,

•a rollercoaster at the bottomof the first big hill,

•a baseball flying through the air.