NAME ______

Chapter 12: Motion

Section 1: Newton’s First and Second Laws – Read pages 397-402 and answer the following.

  1. Determine whether an object’s velocity is being changed by a force in the following situations (answer Yes or No).

______a.A batter hits a baseball upward into right field.

______b.A satellite orbits Earth at a constant speed of
7,000 m/s.

______c.A submarine moves due east at a constant speed of 45 m/s.

______d.A falling book lands on the floor with a pre-collision speed of 9 m/s.

  1. Calculate the acceleration of an 82 kg couch that is pushed across the floor with an unbalanced force of 21 N (p 400) REARRANGE THE EQUATION!
  1. Determine the force needed to accelerate a 1,357 kg car forward at 8.0 m/s2(p 400).
  1. Explain why a backward-facing car seat is safer for an infant than a forward-facing car seat during a collision or abrupt stop (p 398).

______

  1. Use the concept of inertia to illustrate why volleyball is not played with a ball that has a mass similar to a bowling ball (p 398).

______

  1. Determine whether the situations below are an example of Newton’s first law or Newton’s second law -
  2. A skydiver accelerating towards the ground______
  3. A skydiver falling with constant velocity______
  4. A skydiver on the ground at rest______

NAME ______

Chapter 12: Motion

Section 2: Gravity – Read pages 403 - 410 and answer the following.

  1. Explain why free-fall acceleration can be considered a constant for objects falling within a few hundred miles of Earth’s surface (p 407).

______

  1. Explainwhy your weight would be less on the moon than on Earth, even though your mass would not change (p 404).

______

  1. Identify which pair of objects would have greater gravitational force between them. Use the law of universal gravitation to explain your answer (p 406).

______

  1. Predict the path of the cannonball below. To do this, draw a line and arrows in the direction of the cannonball’s flight (p 408-409).

  1. Calculate the mass in kg of an object that weighs 1,225 N on Earth.

NAME ______

Chapter 12: Motion

Section 3: Newton’s Third Law – Read pages 412 - 417 and answer the following.

  1. Identify which of Newton’s three laws of motion specifically applies in each of the following situations (use pages 397, 400, & 412):

______a.You feel a force against the sole of your foot as you take a step forward.

______b.A meteor moving in a straight path changes direction when it flies by Earth.

______c.A full grocery cart that is pushed starts moving and increases speed, but the same push increases its speed even more when the cart is empty.

______d.A skateboard moves faster in the same direction it is pushed.

  1. Use Newton’s third law of motion to explain how two billiard balls, moving toward each other at the same speed, collide and move away from each other at the same speed as before (p 417).

______

  1. Circle which of the following has the greatest momentum (p 414-415):

a 500 kg car moving at 64 km/h

a 250 kg cart moving at 128 km/h

a 1,000 kg truck moving at 32 km/h.

Explain your answer:

______

  1. StateNewton’s third law of motion, and give an example that shows how this law works (p 412).

______

  1. Describehow momentum is calculated (p 414).

______

  1. Which of the following models explains why the action and reaction forces don’t cancel each other when a soccer ball is kicked? (p 412)
  2. The force of the player’s foot on the ball is greater than the force of the ball on the player’s foot
  3. The forces do not act on the same object.
  4. The reaction force happens after the action force.
  5. Calculate the momentum of a 1 kg ball that is moving eastward at 12 m/s (p 414).