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 forward off 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. For every action there is an equal and opposite reaction examples include: a rocket shoots “stuff” down and goes up Recoil: a bullet moves forward as the gun pushes back into your shoulder

If force is held the same… when mass is increased, acceleration 4) Explain how force, mass, and acceleration are related. Not just the formula. F = ma If force is held the same… when mass is increased, acceleration will decreased. If mass is the same, it takes greater force to obtain greater acceleration If acceleration held the same, a larger mass requires a larger force

running standing still walking 5) Draw a graph for the following scenarios: A) A person running fast B) A person walking C) A person that is standing still D) A person running that stops for a water break. standing still walking running

6) Explain the speed graph. Who ran fastest? Albert; he got to 100 meter first! Slowest? Charlie; he took the longest to get to 10 meters

Explain the speed graph. 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 = 50m / 8 sec = 6.25 m/s

Explain the speed graph to the right. D. Who made it to the 20m point first? Charlie; he was there in about 3 seconds! How far was the race? 100 meters

7) Draw and label a picture of balanced forces.

8) Draw and label a picture of unbalanced forces. or even…. 20N 20N

Time (t) = .5 hr (half an hour!) S=d/t = 15Km/.5hr = 30Km/hr 9) Spencer 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/t Distance (d) = 15Km Time (t) = .5 hr (half an hour!) S=d/t = 15Km/.5hr = 30Km/hr Answer: 30 Km/hr

S= d/t Distance (d) = 112Km Time (t) = 1.3 hr 10) Susan is driving her Lamborghini on I-45 heading north. She drove 112 Km to Huntsville in 1.3 hrs. What is Susan’s speed in Km/hr? S= d/t Distance (d) = 112Km Time (t) = 1.3 hr S=d/t = 112Km/1.3hr = 86.15Km/hr Answer: 86.15 Km/hr

S= d/t Distance (d) = 1m Time (t) = .26 s S=d/t = 1m/.26sec = 3.85m/s For a science experiment, Aneeah 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/t Distance (d) = 1m Time (t) = .26 s S=d/t = 1m/.26sec = 3.85m/s Answer: 3.85 m/s

What causes an object to accelerate? 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

F = ma mass (m) = 4.4 Kg acceleration (a) = 1.8 m/s2 13) Antonio lifts a 4.4Kg weight over his head with an acceleration of 1.8m/s2. How much force is Antonio exerting on the weights? F = ma mass (m) = 4.4 Kg acceleration (a) = 1.8 m/s2 F=ma = 4.4Kg x 1.8 m/s2 = 7.92 kg*m/s2 Answer = 7.92 N

F = ma mass (m) = 33 Kg acceleration (a) = 2.2 m/s2 14) Dylan pushes a 33Kg cart with school supplies across the floor by accelerating it at a rate of 2.2m/s2. How much force was applied to the cart. F = ma mass (m) = 33 Kg acceleration (a) = 2.2 m/s2 F=ma = 33Kg x 2.2 m/s2 = 72.6 kg*m/s2 Answer = 72.6 N

F = ma mass (m) = 96 Kg acceleration (a) = 1.1 m/s2 15) David and Mr. Clary compete in a tug-of-war. David pulls Mr. Clary (whose mass is 96Kg) with an acceleration of 1.1m/s2. What force is David applying? F = ma mass (m) = 96 Kg acceleration (a) = 1.1 m/s2 F=ma = 96Kg x 1.1 m/s2 = 105.6 kg*m/s2 Answer = 106.6 N

F = ma Force (F) = 112 N acceleration (a) = 8 m/s2 F=ma Grace applies a force of 112N to a wagon The cart accelerates at 8 m/s2. What is the mass of the cart? F = ma Force (F) = 112 N acceleration (a) = 8 m/s2 F=ma 112N= m * 8 m/s2 Divide both sides by 8! m= 34 Answer = 34 Kg

F = ma Force (F) = 51N mass (m) = 17 Kg F=ma 51N = 17Kg x a 3 m/s2 Caleb applies a force of 51N to a box. The box Has a mass of 17Kg. What is the box’s acceration? F = ma Force (F) = 51N mass (m) = 17 Kg F=ma 51N = 17Kg x a Divide both sides by 17 3 m/s2 Answer = 3 m/s2

for example: 68 miles per hour north 18) What is velocity? Speed with direction for example: 68 miles per hour north or 28 m/s down the ramp

19) 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 between two of Earth’s plates.

20) What is kinetic energy? Energy of motion….. Examples include: an apple falling, a rollercoaster at the bottom of the first big hill, a baseball flying through the air.