Equations of motion

Question 1

The three equations of motion can be used ……………. They are only applicable to motion in a straight
line where acceleration is uniform.

Answer 1

instead of calculating the area under the graph or the slope of a graph

Question 2

When doing equations of motion what question should we always ask ourselves? And what should the answer be?

Answer 2

Have all the forces (push & pulls) been constant from the initial to the final point?

To use the equations of motion correctly, the answer to the question above should always be yes.

Question 3

Initial velocity (u), final velocity (v), acceleration (a) and displacement (s) are \_\_\_\_\_! Directions are therefore very important. Always choose a particular
direction of motion as \_\_\_\_\_.

Answer 3

VECTORS

Positive

Question 4

Motion in the opposite direction is ______.

Answer 4

Negative

Question 5

• When the velocity and the acceleration are in the same direction the object ____ _____.
• When the velocity and the acceleration are in opposite directions the object ____ ______.

Answer 5

speeds up

slows down

Question 6

For an object starting from rest, ___ = 0 m.s1

For an object that comes to rest, ___ = 0 m.s1

Answer 6

U

V

Question 7

• For an object dropped from an object which is not moving, ___ = 0 m.s1
• For an object dropped from a moving vehicle, u = ___________________.

Answer 7

U

velocity of the moving vehicle

Question 8

The weight of an object is a force acting on the object. The _____ is the gravitational pulling force of the earth on the object. The size of the pulling force depends on the mass of the object. Objects with greater ____ experience a greater gravitational pulling force.

Answer 8

Weight

Mass

Question 9

An object that is thrown in some way is called a _____. The equations of motion still apply and gravitational acceleration still has to be taken into account. The difference is that the initial velocity is not ____.

Answer 9

projectile

zero

Question 10

The acceleration is always _____ as the weight is always acts down. This is true even when an object moves upwards. When the velocity and the acceleration
are in the same direction the object _____ ____. When the velocity and the acceleration are in opposite directions the object ____ ____.

Answer 10

downwards
speeds up
slows down

Question 11

The velocity at the highest point, for an object thrown upwards, is ____.

Answer 11

Zero

Question 12

What is terminal velocity?

Answer 12

Terminal velocity is the maximum velocity attained by an object which has a constant applied force acting on it while moving through a frictional medium.

Question 13

Velocity is always measured relative to something called a \_\_\_\_\_ \_\_\_\_. A reference frame can be stationary or moving. All velocities in this module are
relative to a moving reference frame, the earth. The speed of the earth does not affect our calculations because all of the velocities were taken relative to the same reference frame. When we say that a car is moving at 120 km.h1 , it is assumed that the velocity is relative to \_\_\_\_\_\_. The earth is treated as if it were \_\_\_\_\_.

Answer 13

reference frame
earth
stationary