Kinematics

Question 1

Define distance

Answer 1

Distance is the length of the path taken. It is a scalar quantity

Question 2

Define displacement

Answer 2

Displacement is the distance travelled along a specified direction. It is a vector quantity

Question 3

Define speed

Answer 3

Speed is the rate of change of distance. It is a scalar quantity

Question 4

Define velocity

Answer 4

Velocity is the rate of change of displacement. It is a vector quantity.

Question 5

Define acceleration

Answer 5

Acceleration is the rate of change of velocity

Question 6

What does the gradient of a point in a displacement-time graph show

Answer 6

It shows the velocity at that point

Question 7

What does the gradient of the at a point in a velocity time graph show

Answer 7

instantaneous acceleration

Question 8

What is does the area under the graph of a velocity-time graph show

Answer 8

displacement

Question 9

What does the the area under an acceleration-time graph represent

Answer 9

change in velocity

Question 10

Explain free fall in the absence of air resistance

Answer 10

In the absence of air resistance, an object is said to be in free fall if the only force acting on the it is the weight due to the earth. The downward acceleration is know as the acceleration due to the gravity due to 9.81. The object continues accelerating for the duration of free fall.

Question 11

Explain free fall in the presence of air resistance.

Answer 11

As an object falls through the air, it experiences a drag force opposing its motion. Drag force is proportional to speed of the object. As it falls, the speed/velocity of the object increases until the drag force balances its weight. The velocity remains constant and this max velocity is called terminal velocity.

Question 12

What are the 4 kinematic equations for uniformly accelerated motion in a straight line

Answer 12

• v = u + at
• s = 1/2(u + v)t
• s = ut + 1/2(at^2)
• v^2 = u^2 + 2as