# Newton S Laws Review

**Unit Two Review: Newton’s Laws and Projectile Motion Name ______**

Overview:

The student will measure and calculate the magnitude of frictional forces and Newton’s three laws of motion.

The student will calculate the magnitude of gravitational forces.

The student will calculate two-dimensional motion (Projectile and inclined plane) by using component vectors.

The student will calculate changes in apparent weight in accelerated systems

- What is inertia?

- What are two conditions of motion that are equal under Newton’s First Law?

- Does mass change? If so, when?

- Does weight change? If so, when?

- Name three things that are true of friction.

- How do you add 20 newtons East to 5 newtons West?

- How do you add 20 newtons East to 10 newtons North?

- According to Newton’s 2nd Law, what causes acceleration?

- Describe terminal velocity.

- Two ropes support a swing on a playground. The weight of the child in the swing is 300 Newtons. How much does each rope support? What if we had four ropes?

- A human cannonball is pulled to the Earth with a force of gravity equal to 700 newtons. Describe the reaction force. Which law is that?

- A volleyball player lobs a ball across the net with components of velocity as follows: up at 8 m/s and East at 3 m/s. (Ignore the height of the player)

- How long will the ball stay in the air?
- How far east will it travel in that time?
- When does the ball reach its highest point?

- Suppose we launch a grand piano at 20 m/s, 30 degrees above the horizontal. Find the answers to the same three questions as above.

- Daredevil Fergie Fizzical zooms his racecar @ 12 m/s horizontally off a cliff 16 meters high.
- How long is he in the air?

- Where does he splat?

- If you have two objects:one that is 10 kg and one that has 29 kg, which has more inertia? More weight? Falls to earth faster?
- The moon has _____the gravitational pull of the Earth.

- Weight= mass x gravity. Then if you have a 10 kg rock what is its weight on Earth? On the moon? The mass there?

- If an object is going to accelerate there must be a______acting on it.

- What is terminal velocity?

- If you push on a wall with a force of 20 N how much force does the wall exert on you?

- What are action-reaction pairs?

- When a baseball player hits a ball with a bat, the bat exerts a force on the ball and the ball ______.

- What force is exerted on all falling objects? How much is that force per kilogram?

- When a baseball player hits a ball with a bat which object has the greatest change in velocity? Why?

- State Newton’s third law. Give an example you see in everyday life.

- Using physics terms explain why we slide on ice and not bricks.

- Find the friction force that causes a 2000 kg car to go from 15 m/s to a stop in 5.0 sec. Can you find mu?

- If you push with 30 N on a 30-kg dresser, and there is someone pushing against you with 10N of force, how fast will the dresser accelerate? Hint: Find net force first.

- How do we represent Newton’s Second Law? What do the letters stand for?

- Can you do the same for Newton’s 3rd Law?

- If a can is sitting on a table, what forces are acting on it?

- Suppose the can is sliding down an icy mountainside/ ski jump, draw the forces acting then.

- Assume the can above is 2 kg and the hill is 20 degrees. Find the weight and normal forces.

- Now find the vector sum of the two forces (the net force down the hill).

- Use your knowledge of Newton’s Law to explain why seat belts should be worn.

- An 18 kg poodle (Fifi Fizzical) is standing in an elevator moving up at 8 m/s. What is her apparent weight?

- What if the elevator accelerates up at 8 m/s2? Why the change?