9702/Oct Nov/13/2015/Q11

Question 11

A rocket of mass 30 000 kg sits on a launch pad on the Earth’s surface. The rocket motors
provide an upward force of 330 kN on the rocket.

What is the initial acceleration of the rocket?

A     0.12 m s^–2
B     1.1 m s^–2
C     1.2 m s^–2
D     11 m s^–2

Solution:
30 000kg x 9.81 = 294 300N
330 000 - 294 300 = 35700N
ma = 35700N
a = 35700/30000
   = 1.19
   = 1.2 ms^-2

Ans: C

Reference: PYQ - Oct/Nov 2015 Paper 13 Q11