ROTATIONAL MOTION 1

 

 

1. A rocket’s acceleration function is described by:

(a) Derive the velocity function, if at t = 0, the velocity is 10ms^-1.

(b) Derive the displacement function if the initial displacement is 50m.

(c) Calculate the displacement of the rocket when t = 10s.

 

2.  A body moves with displacement function s = 4 + 12t – t³.

(a) When will it stop and reverse its direction of motion?

(b) Find its acceleration when t = 0.

(c) Find its acceleration at the time it reverses its direction.

(d) How can you tell from the position equation that the acceleration is not constant?

 

3.  If the Moon rotates about the Earth in a circular path of radius 3.85 x 10⁸m, with a period of 27.3 days, find;

(a) Its angular velocity.

(b) Its speed relative to the Earth.

 

4.  A point on the rim of a train wheel of diameter 1.2m decelerates from 30ms^-1 to 18ms^-1 in 12s. Calculate;

(a) The angular deceleration

(b) The distance travelled by the train during this time.

 

5.  A string 2.0m long is attached to a fixed point as shown.

A lead sphere of mass 75g is attached to the other end. If the sphere describes a horizontal circle of radius 1.0m with a steady speed, find;

(a) The tension in the string.

(b) The period of the pendulum.