Question

35. O/N 10/P12/08
A moving body undergoes uniform acceleration while travelling in a straight line between points X, Y and Z. The
distances XY and YZ are both 40m. The time to travel from X to Y is 12s and from Y to Z is 6.0s.
What is the acceleration of the body?
A 0.37m2
B 0.49ms-2
C 0.56ms-2
D 1.1ms-2

Answer 1

Answer: A 0.37m/s2

Explanation:You have the four equations of motions. Select the one which is best to use in this situation. That is s = ut + ½at²

Make a system of equations.

1. For t = 12, 40 = 12u + ½a (12)²

2. For t = 6, 40 = 6v + ½a (6)²; v here is the speed it has at Y.

v= u + at = u + 12a ⇒ For t = 6, 40 = 6( u + 12a) + ½a (6)²;

We must find a, therefore we extract u from the first equation.

u = (40 – 72a) / 12

and replace it in equation number two.

40 = 6[ (40-72a)/12 + 12a] + ½a (6)²

this will give a = 0.37 m/s/s