Question

a racing car is moving with a velocity of 50m/s on applying brakes, it is uniformly retarded and comes to rest in 20 seconds. Calculate its acceleration.

Answer 1

@
u=50m/s
v= 0
t=20sec
a=?
___________
v=u+at
0=50+20a
-50=20a
-50/20=a
-2.5m/s²=a
acceleration= -2.5m/s²
@:-)

Answer 2

Concept:

A motion is an event in which an object changes its position with respect to space and time.

Given:

The initial velocity of the car, $u=50m/s$ .

The final velocity of the car, $v=0m/s$ .

Time, $t=20sec$ .

Find:

The acceleration of the racing car.

Solution:

Initial velocity, $u=50m/s$

Final velocity, $v=0m/s$ as the racing car comes to rest.

Time, $t=20sec$ .

Now, using the first equation of motion.

$v=u+at\\0=50+a(20)\\a=-\frac{50}{20}m/s^2\\ a=-2.5m/s^2$

The acceleration of the racing car is $-2.5m/s^2$ .

#SPJ2