Question

5. A drag racer starts her cas
from rest and accelerates
at 10.0 m/s2 for the entire distance of 400m.How long did it take the race car to travel this distance in
(a) 9.01
(b)8.33
(c) 10.2
(d) 8.94​

Answer 1

Answer:

d). 8.94

Explanation:

a=10ms^-2

s=400m

u=0

Use 2as =v^2 -u^2 to find v and then find t using v = u + at .

Answer 2

Given:

A drag racer starts her car from rest and accelerates at 10.0 m/s² for the entire distance of 400m.

To find:

Time taken ?

Calculation:

Let time taken to travel the distance be 't':

Applying EQUATIONS OF KINEMATICS:

$d = ut + \dfrac{1}{2} a {t}^{2}$

$\implies \: 400 = (0 \times t) + \dfrac{1}{2} (10) {t}^{2}$

$\implies \: \dfrac{1}{2} (10) {t}^{2} = 400$

$\implies \: 5 {t}^{2} = 400$

$\implies \: {t}^{2} = 80$

$\implies \: t = \sqrt{80}$

$\implies \: t = 8.94 \: sec$

So , time taken by racer is 8.94 seconds.