Question

The distance travelled in t seconds by an object starting with a speed
of u metres/second and moving along a straight line with speed
increasing at the rate of a metres/second every second is given by
ut + at metres. An object moving in this manner travels 10 metres in
1 1/2
2 seconds and 28 metres in 4 seconds. With what speed did it start? At
what rate does its speed change?​

Answer 1

Step-by-step explanation:

Given S=ut+

2

1

at

2

.....(1)

Case:1 S=10m and t=2sec

Putting value of S and t in equation 1

∴10=2u+2a⇒u+a=5....(2)

Case:2 S=28m and t=4sec

Putting value of S and t in equation 1

∴28=4u+8a⇒2u+4a=14....(3)

Multiplying equation (2) by a and subtracting from equation (3)

2u+4a=14

−2u−2a=−10

2a=4⇒a=2

Putting the value of a in equation (2)

u+a=5⇒u=5−a=5−2=3

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