Kinematics

Question 1

Displacement of a point

Answer 1

Displacement of an object is its distance from a fixed point in a specific direction.

Question 2

Velocity

Answer 2

The rate of change of body’s displacement with respect to time

Question 3

Acceleration

Answer 3

The rate of change of a body’s velocity with respect to time

Question 4

formula for v

Answer 4

u + at

Question 5

Formula for s

Answer 5

½(u+v)t
ut+½a(t)^2

Question 6

Formula for v^2

Answer 6

u^2 + 2as

Question 7

Low speeds with no turbulence

Answer 7

F = kv

Question 8

High speeds with turbulence

Answer 8

F = kv^2

Question 9

Why does an object reach a constant velocity?

Answer 9

When the object is dropped, air resistance which acts opposite to the object’s motion increases as speed of object increases.

The resultant force on the object (diff between weight and air resistance) decreases as the object falls.

When magnitude of air resistance is equal to the objects weight, resultant force becomes zero, and object reaches constant velocity.

Question 10

Show that a falling body will accelerate with a value lower than g when there is no air resistance, using equations.

Answer 10

F(net) = ma
W - R = ma
mg - R = ma
a = g - (R/m)