Big Idea 12 Motion of Objects

In PE we played soccer on a flat field. One child kicks the ball and it rolled across the field. Which statement best explains the motion of the ball?

• The ball will roll until a force acts on it.

• The ball will speed up as it crosses the field.

• The energy in the ball will increase as it rolls.

• The ball will roll continuously unless it hits something.

Answer explanation

If you kick a ball on a flat surface it will roll forever unless some sort of forces act on it! As strange as this may sound, it's true. When you kick a ball, forces start to act on it immediately. These include resistance or friction from the air and gravity. Gravity pulls the ball down to the ground and the air resistance slows it down.

WOW!!!!

This is known as Newton's First Law

Yoda presented four scenarios to his Jedi class they all describes an object in motion. Which of the following also describes a change in direction of an object’s motion?

• BB8 rolled 11 feet before stopping.

• A Stormtrooper ran straight to catch the ball.

• Baby Yoda's kite is flying north it was blown by the wind to the west.

• A long time ago in a galaxy far, far away Luke walked 200 mile in 20 light years.

Answer explanation

Use the Forces ~ it affect how objects move. They may cause motion; they may also slow, stop, or change the direction of motion of an object that is already moving. Since force cause changes in the speed or direction of an object, we can say that forces cause changes in velocity.

Mrs. G is moving different objects in her classroom. Which of the following would require her to use the most force to move the object?

• pulling her desk across the room

• pushing her chair across the room

• pushing her book across the desk

• pulling her lunch box across the desk

Answer explanation

An Applied force is a force applied to an object an object to make it move, for to make it move, for example: a example: a person moving furniture, person moving furniture, the person is applying a force to make the furniture move. Inertia is the property of all things property of all things due to mass, the more mass something has the more inertia it has this can make things harder or easier to move

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How can you decrease the speed of the car when rolling down a ramp?

• by raising the ramp

• by pushing it harder

• by lowering the ramp

• by decreasing the friction

Answer explanation

If you decrease the steepness of the ramp, then you will decrease the acceleration of a carl which rolls down the ramp.

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Which of the following objects will have the greatest change in its motion?

• A large force is applied to an object with a large mass.

• A large force is applied to an object with a small mass.

• A small force is applied to an object with a large mass.

• A small force is applied to an object with a small mass.

Answer explanation

Two objects with different weights (mass) will need different forces to move them and the acceleration levels will be different.

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Clark and Parker left school at the same time. Clark lives farther away, but arrived at his home at the

same time that Parker arrived at his home. Which describes their speed?

• They traveled at the same rate.

• Parker traveled at a faster rate of speed.

• Clark traveled at a faster rate of speed.

• There is not enough information to describe their speed.

Answer explanation

Speed is the distance that an object moves in a given amount of time. Speed is a measure of how fast something is moving. The average speed of an object in a certain time is the distance the object traveled divided by the time.

Violet kicked her soccer ball into the air, but after a few seconds the soccer ball started to fall back

toward her. What force made the soccer ball change direction without directly coming into contact with

the soccer ball?

• mass

• gravity

• friction

• air pressure

Answer explanation

Gravity or gravitational forces are forces of attraction. It's like the Earth pulling on you and keeping you on the ground. That pull is gravity at work. Every object in the universe that has mass exerts a gravitational pull, or force, on every other mass.

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Quinn recorded the time it took for her to get home on the bus from school for an entire week. The table

shows the time for each day.

Which day did the bus travel with the least speed?

• Friday

• Monday

• Tuesday

• Wednesday

Answer explanation

Speed relates to how fast something is moving and how fast it moves over a distance. For example, something moving very fast, like a train, can cover a large distance in a short time. Something moving slowly, like a walking man, will travel a very short distance in the same amount of time

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If a paper airplane is moving at a constant speed and no other forces are applied, what will happen to the ball’s

motion?

• It will speed up.

• It will slow down.

• It will come to a stop.

• It will remain constant.

Answer explanation

An object will stay still or keep moving at the same speed and in a straight line, unless it is acted upon by an outside force.

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If an object has no speed, which of the following correctly describes the object’s motion?

• The object is moving slowly.

• The object is changing direction.

• The object is changing its position.

• The object has forces acting on it which are in balance.

Answer explanation

Balanced forces are those that are opposite in direction and equal in size. Balanced forces are considered to be in a state of equilibrium. When forces are balanced there is no change in direction.

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