# Home Work 3 U4

```Name: _______________________________
Date: ________________________________
Motion
Motion is the movement in which an object changes it position. A person may know
an object moved and motion has taken place by looking at the other objects nearby.
For example, while on a boat it may not feel like it is moving, but as the boat drifts
along the shore, the view changes.
A frame of reference can be created after a reference point is chosen relative to
the position of an object. For example, a person on a train car can seem to be moving,
but it is actually the train car moving and the person is still. The person's position does
not change. The frame of reference is the person on the train, which shows that the
train is moving.
Velocity includes how fast an object is in motion or its speed plus its
direction. Speed can be determined using different measurements over a period of
time to determine how fast an object is moving. For example, the speed of a car may
be measured at 50 miles per hour. The car will travel a distance of 50 miles in one
hour, which is the unit of time. Speed can be measured per hour, per minute, per
second, and others. The velocity of a storm tells meteorologists the direction of a
hurricane which will help residents to prepare for the hurricane to remain safe. The
velocity is the speed and direction of a moving object.
Acceleration is the force applied to an object changing its speed, direction, or both.
Acceleration may increase or decrease the speed or velocity of an object. For example,
when a person is driving a car they may use acceleration to cause it to move faster.
When a person is walking and decides to start running, the person will accelerate by
using leg muscles to help them run faster.
Deceleration is also a force applied to an object changing its speed, direction, or
both. Deceleration is a type of acceleration that will decrease the speed or velocity of
an object. An example of deceleration is a person driving a car decides to slow down by
pressing on the brake. It can also include a runner slowing down to rest while running a
marathon.
Friction is a force that will also affect the motion of an object. Friction is the force
that opposes the sliding motion between two touching surfaces. In other words, friction
can affect the speed of an object's movement, usually by decreasing the speed.
Examples may include a person moving a piece of furniture on a carpeted floor. The
carpet makes it more difficult to move it and the couch does not slide quickly across the
floor; its speed decreased. A sled on snow may not slide so quickly sometimes because
friction between the rudders and snow may decrease its speed. Friction will affect how
quickly a person can rub their hands together. The more friction there is the more
difficult it will be for the person to rub their hands together.
There are many other variables affecting motion as well, including the weight of the
object, the amount of force, temperature, size, and several other variables. Even
gravity may affect the motion of an object. People who have landed on the moon move
very easily because there is little or no gravity. While on Earth gravity affect their
movement or motion.
In summary, motion is the movement in which an object changes its position. Using
a frame of reference, it is possible to prove something moved. Acceleration and
deceleration will affect the speed and velocity of an object in motion, and friction
usually decreases the speed of an object's motion.
1) Which of the following can best be described as speed plus direction?
A: Acceleration
B: Deceleration
C: Friction
D: Velocity
2) Which of the following may increase or decrease the speed of an object?
A: Acceleration
B: Deceleration
C: Motion
D: Frame of reference
3) A force that opposes the sliding motion between two objects is which of the
following?
A: Acceleration
B: Deceleration
C: Friction
D: Gravity
4) If a person is riding a bike and want to slow down, they use the brakes. This is an
example of which of the following?
A: Frame of reference
B: Motion
C: Deceleration
D: Velocity
5) Which of the following may be causing trouble for a person moving a chair across the
room?
A: Friction
B: Velocity
C: Motion
D: Speed
6) The boy sat in the car so long it felt like he was no longer moving, but then he saw a
tree that was beginning to get further and further away from his view. The tree is which
of the following?
A: Friction
B: Frame of reference
C: Velocity
D: Gravity
C) After you have finished, add the following words to your glossary.
Please note similar questions may be on your weekly quiz on Friday.
Words: Velocity, Speed ,
of reference.
Motion , Acceleration , Deceleration, Friction, Frame
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