Motion and Force Review

Motion is a change in Position over time Speed over time Velocity over time Acceleration over time

Position over time

Bob walks 100 m in 50 s, moving at different speeds Bob walks 100 m in 50 s, moving at different speeds. Dividing 100 m by 50 s gives you Bob’s Acceleration Average speed Direction velocity

Average speed

Sue is riding her bicycle. She begins pedaling harder Sue is riding her bicycle. She begins pedaling harder. What do you predict will happen? Her velocity will decrease Her acceleration will decrease Her speed will increase Her position will not change

Her speed will increase

Speed in a specific direction is Acceleration Distance Position velocity

velocity

Susie walked north at 100m/s Susie walked north at 100m/s. Mack had a different velocity but het same speed. He could have walked North at 200 m/s South at 50 m/s West at 100 m/s North at 100 m/s

West at 100 m/s

Clint drives at a steady velocity. Her acceleration is Equal to zero In the same direction as her motion Opposite to her motion At a right angle to her motion

Equal to zero

Acceleration measures a change in Location Direction Position velocity

velocity

Lisa is watching a friend run a race Lisa is watching a friend run a race. What does she need to know to find her friend’s speed Distance and time Position and motion Distance and position Time and motion

Distance and time

Hallie walked 18 m in 12 s. She did not walk at a steady speed, so 1 Hallie walked 18 m in 12 s. She did not walk at a steady speed, so 1.5 m/s was her a) acceleration b) average speed c) direction d) velocity

b) average speed

What is an example of zero acceleration? A school bus coming to a stop An ice hockey player turning around A person walking on a treadmill at a steady rate An airplane speeding up along a runway

A person walking on a treadmill at a steady rate

Zeus walks one mile west Zeus walks one mile west. Missy walks one mile east in the same amount of time. They have The same velocity Different average speeds Different velocities The same location

Different velocities

Velocity is different from speed because velocity also includes Motion Direction Distance Acceleration

Direction

Hannah jogged 200 m in 25 seconds and then 100 m in 15 seconds Hannah jogged 200 m in 25 seconds and then 100 m in 15 seconds. She could find his average speed by dividing 200 m by 40 s 300 m by 25 s 300 m by 40 s 100 m by 15 s

300 m by 40 s

Melanie is accelerating as she skates on the ice Melanie is accelerating as she skates on the ice. However, the speed at which she is skating has not changed. A possible explanation for this is that Melanie Is skating in a wide circle Is skating in a straight line Has reached the top speed at which she can skate Has stopped skating and is now standing still

Is skating in a wide circle

A push or pull is called Motion Force Acceleration velocity

Force

Willie combines all the forces acting on a tennis ball Willie combines all the forces acting on a tennis ball. He is finding the Net force Inertia force Gravitational force Frictional force

Net force

DT is sliding a box across the floor DT is sliding a box across the floor. What do he need to know to calculate the force on the box? Mass and inertia Acceleration and friction Mass and acceleration Friction and gravity

Mass and acceleration

Inertia is the resistance of an object to a change in its Gravity Motion Mass Balanced force

Motion

A soccer player kicks a ball that is at rest A soccer player kicks a ball that is at rest. What do you predict will happen? The ball will not move The ball will lose momentum The ball will accelerate in the opposite direction the applied force The ball will accelerate in the same direction the applied force

The ball will accelerate in the same direction the applied force

According to Newton’s second law of motion, force equals mass times Velocity Momentum Acceleration mass

Acceleration

The momentum of an object is the product of its Mass and acceleration Mass and velocity Force and mass Net force and mass

A bowling ball rolls down the lane and hits some pins before rolling off the lane. What happens to the momentum of the ball as it hits the pins? Some of the ball’s momentum is transferred to pins All of the ball’s momentum is transferred to pins None of the ball’s momentum is transferred to pins Pins stop the ball from rolling farther

Some of the ball’s momentum is transferred to pins

If one force is balance by another force, the Effect is the same as no force at all Effect is a positive force Size of the first force is balance by the direction of the second force The direction of the first force is balance by the size of the second force

Effect is the same as no force at all

One way to decrease acceleration is to Decrease force and mass equally Increase force more than mass Increase mass Decrease mass

Increase mass

Centripetal force keeps an object moving in a circle. The force points Toward the center of the circle Toward the out edge of the circle To the right of the center of the circle Away from the circle in all directions

Toward the center of the circle