Question

If body starts from rest and travels 1.2 m in the 8th second then what is the acceleration
(1) 0.20 m/s^2
(2) 0.16 m/s^2
(3) 0.08 m/s^2
(4) 0.2255 m/s^2​

Answer 1

Answer:

The information given in the problem is for the interval from B to C, so we will begin by writing an equation of motion for that interval.

Applying Newton’s equation of motion,

From B to C (time interval = 1 sec):

S=Vit+1/2at2

or

SB−C=VBt+12at2

120cm=VB(1sec)+12a(1sec)2

or

120=VB+12a ————--- eqn 1

This equation has 2 unknown variables, so we need another equation to solve it. The only other information we know is that the body starts from rest at A, so let's write an equation of motion for the interval A to B:

2. From A to B (time interval = 5 seconds):

Vf=Vi+at

or

VB=VA+at

VB=0+a(5)

Substitute this into equation 1:

120=a(5)+12a

a=21.82cms or 0.218ms

Answer 2

By using the formula you can get the answer