Question

A running truck at 54 km/hr is bought to rest in 10s. The distance travelled by the truck in 10^th second is:
1. 0.75 m
2. 0.25 m
3. 0.90 m
4. 0.50 m

Answer 1

Correct Answer - Option 1 : 0.75 m

Concept:

Equations of Motion

The following three equations are considered under motion in a straight line when there is a uniform acceleration.

v = u + at -- (1)

\(s = ut + \frac{1}{2}at^2\) -- (2)

v2 = u2 + 2ah -- (3)

s = u + a (n - ½) --(4)

u is initial velocity, v is final velocity, a is acceleration, t is the time interval, s is the travelled distance, n is the distance travelled in n^th sec.

Calculation:

Given: u = 54 km/hr = 15 m/s, v = 0 m / s, t = 10 s.

From the equation:

v = u + at

0 = 15 + a × 10

a = - 1.5 m/s²

From the travelled distance in n^th sec formula:

s = u + a (n - ½)

s = 15 - 1.5 (10 - ½)

s = 0.75 m