Question

20. For a body starting from rest, the distance travelled
(d) is directly proportional to the square of the time
elapsed from the start (t). When t = 4 sec, d = 48 m.
What is the value of d (in metres) at t = 7sec?
(A) 128 (B) 150 (C) 115
(D) 147
​

Answer 1

Answer:

Given- S=Ct², Where S stands for displacement, C is a constant and T is time in S.

Step-by-step explanation:

When t=4

$48 = c {(4)}^{2}$

$c = \frac{48}{16}$

$c = 3$

Now when T=7

we have

$d = 3( {7}^{2} )$

$d = 3 \times 49$

$d = 147$

Therefore displacement is 147m.Hence correct answer is D