Unit 2: Force s & Motion Post Review

Alfonso, Julia, and Margie were having fun as they rolled some office chairs across a flat floor. All three chairs have the same mass. Margie gave each of the chairs a push, but not all from the same direction. Each chair changed speed as a result of being pushed. Which chair(s) experienced the strongest force when it was pushed? How do you know?

• The black chair experienced the strongest force because it takes a stronger force to slow something down than it takes to speed something up.

• The blue chair experienced the strongest force because it had the fastest ending speed.

• All three chairs experienced the same strength force because they changed speed by the same amount.

Answer explanation

The blue chair experienced the strongest force because it had the fastest ending speed. According to Newton's second law, a greater change in speed indicates a larger force was applied.

Tags

NGSS.MS-PS2-2

Three boats were moving across the surface of a smooth lake. The gray and pink boats have the same mass, and both of these boats are more massive than the orange boat. Each boat was bumped by another boat, but not from the same direction. Use the information in the diagram to answer. Which boat(s) experienced the strongest force when hit? How do you know?

• The gray and pink boats experienced the strongest force because they are both more massive than the orange boat, and they all changed speed by the same amount.

• The pink boat experienced the strongest force because it is as massive as the gray boat and has the highest ending speed.

• All three boats experienced the same force because they changed speed by the same amount.

Answer explanation

The pink boat experienced the strongest force because, despite having the same mass as the gray boat, it achieved the highest ending speed, indicating a greater change in momentum.

Tags

NGSS.MS-PS2-1

Alice and Kai were playing air hockey, which is a game where players hit a puck with paddles so the puck slides across a table. After the game, they were crashing the puck and two different paddles. The puck was the same in both crashes, but the paddles were different: the red paddle had less mass, while the purple paddle had more mass. Use the information in the diagram to answer. In which crash did the puck experience a stronger force? Why?

• The puck did not experience a force; only the paddles experienced a force in the crashes.

• Crash 2; the force on the purple paddle was stronger in this crash, so the force on the puck was also stronger.

• The diagram doesn’t tell you anything about the force on the puck. It only gives information about the force on the paddles.

• The puck experienced the same force in both crashes. The paddles

Answer explanation

In Crash 2, the purple paddle, which has more mass, experienced a stronger force. According to Newton's third law, the force exerted on the puck is equal to the force exerted on the paddle, making the force on the puck stronger in this crash.

Tags

NGSS.MS-PS2-1

In soccer, players kick a soccer ball across a flat field. At practice one day, three soccer balls that have the same mass were rolling across the field. They were each kicked by a soccer player, but not from the same direction. Each soccer ball changed speed as a result of being kicked. Use the information in the diagram to answer. Which soccer ball(s) experienced the strongest force when it was kicked? How do you know?

• The purple soccer ball because it has the fastest ending speed.

• The blue soccer ball because it takes a stronger force to slow something down than to speed something up.

• The blue soccer ball because it changed speed the most.

• The purple and yellow soccer balls because they gained force, while the blue soccer ball lost force.

Answer explanation

The blue soccer ball experienced the strongest force because it changed speed the most. A greater change in speed indicates a larger force applied, according to Newton's second law of motion.

Tags

NGSS.MS-PS2-1

Three skiers were racing across flat, smooth snow. The skiers in yellow and purple sweaters have the same mass, which is more mass than the skier in the red sweater. Each skier was bumped by another skier, but not from the same direction. Use the information in the diagram to answer. Which skier(s) experienced the strongest force when bumped? How do you know?

• All three skiers experienced the same force because they changed speed the same amount.

• The purple skier; he is more massive and has the fastest ending speed.

• The yellow skier; it takes a stronger force to slow down a more massive object than to speed it up.

• The yellow and purple skiers; they have more mass than the red skier, but changed speed by the same amount.

Answer explanation

The yellow skier experienced the strongest force because it takes a greater force to slow down a more massive object. Since the yellow skier has more mass than the red skier, the force required to change its speed is greater.

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

Engineers are designing a new car and they need to test their ideas by modeling crashes with different types of trucks. They are using a more massive garbage truck for Crash 1 and a less massive pickup truck for Crash 2. The green test car has the same mass in both crashes. Use information from the diagram to answer. In which crash did the green test car experience a stronger force? How do you know?

• Crash 1; the force on the garbage truck was stronger in this crash, so the force on the green test car was also stronger.

• There is no force on the green car. In each crash, only the truck experienced a force.

• It was the same from both crashes. The trucks changed speed by the same amount in both crashes, so the force on the test car was the same both times.

Answer explanation

In Crash 1, the garbage truck's greater mass results in a stronger force during the collision. According to Newton's third law, the force experienced by the green test car is equal and opposite to that on the garbage truck, making it stronger in Crash 1.

Tags

NGSS.MS-PS2-1

Hockey is a sport in which athletes use hockey sticks to hit a puck across smooth ice. At practice one day, three hockey pucks (all with the same mass) were sliding across the ice. A player hit each puck with a hockey stick, but not from the same direction. Each puck changed speed as a result of being hit. Use the information in the diagram to answer. Which hockey puck(s) experienced the strongest force when hit? How do you know?

• The black puck because it takes a stronger force to slow something down than to speed it up.

• All three hockey pucks experienced the same strength force because they changed speed by the same amount.

Answer explanation

All three pucks changed speed by the same amount, indicating they experienced the same strength of force. The direction of the force does not affect the magnitude when the change in speed is equal.

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

Miniature golf is a game in which players hit a golf ball with a club. This causes the ball to roll along the flat ground. There were three golf balls rolling on the ground. The yellow golf ball has less mass than the blue and white balls, which have equal mass. Each ball was hit by a golf club, but not from the same direction. Use the information in the diagram to answer. Which golf ball(s) experienced the strongest force? How do you know?

• The blue golf ball; it has more mass and the fastest ending speed.

• All three golf balls experienced the same force because they changed speed by the same amount.

Answer explanation

All three golf balls experienced the same force because they changed speed by the same amount. Force is related to the change in speed, not just mass or final speed.

Tags

NGSS.MS-PS2-2

Eugene and Van were playing with toys in a swimming pool. They crashed a rubber duck into two toy boats: a blue boat with less mass and an orange boat with more mass. The rubber duck had the same mass in both crashes. Use the information in the diagram to answer. In which crash did the rubber duck experience a stronger force? How do you know?

• There is no force on the rubber duck. Only the toy boats experienced a force in those crashes.

• The diagram doesn’t tell you anything about the force on the rubber duck. It only gives information about the force on the toy boats.

Answer explanation

The correct choice is that the diagram doesn’t tell you anything about the force on the rubber duck. It only provides information about the forces acting on the toy boats, not the rubber duck itself.

Tags

NGSS.MS-PS2-1

Juno, Melissa, and Anna have skateboards that are the same mass. They were playing with their skateboards on a flat street when another skateboard came along and bumped their skateboards, but not from the same direction. Each skateboard changed speed as a result of being bumped. Use the information in the diagram to answer. Which skateboard(s) experienced the strongest force when bumped? How do you know?

• The green skateboard experienced the strongest force because it changed speed the most.

• The green skateboard experienced the strongest force because it takes a stronger force to slow something down than it takes to speed something up.

• The red and brown skateboards experienced the same strength force because they both gained force, but the green skateboard lost force.

• The red skateboard experienced the strongest force because it has the fastest ending speed.

Answer explanation

The green skateboard experienced the strongest force because it changed speed the most. A greater change in speed indicates a larger force was applied, confirming that it was affected more significantly than the others.

Tags

NGSS.MS-PS2-1