Q. 154.0( 8 Votes )

# A body starts to slide over a horizontal surface with an initial velocity of 0.5 m/s. Due to friction, its velocity decreases at the rate 0.105 m/s^{2}. How much time will it take for the body to stop?

Answer :

Using the first equation of motion: v = u + at

where: v = final velocity = 0 m/s

u = initial velocity = 0.5 m/s

a = acceleration = -0.105 m/s^{2}

t = time = ??

v = u + at

0 = 0.5 - 0.105 x t

0.105 x t = 0.5

t = s =4.76 s

Rate this question :

A cheetah starts from rest, and accelerates at 2 m/s^{2} for 10 seconds. Calculate :

(a) the final velocity

(b) the distance travelled.

Lakhmir Singh & Manjit Kaur - PhysicsObtain a relation for the distance travelled by an object moving with a uniform acceleration in the interval between 4^{th} and 5^{th} second.

A car accelerates from 6 ms^{–1} to 16 ms^{–1} in 10 sec. Calculate (a) the acceleration and (b) the distance covered by the car in that time.

A bus increases its speed from 36 km/h to 72 km/h in 10 seconds. Its acceleration is :

Lakhmir Singh & Manjit Kaur - PhysicsA bus is moving with a speed 72 km/h can be stopped by brakes after at least 10 m. What will be the minimum stopping distance, if the same bus is moving at a speed of 144 km/h?

All In One - ScienceDerive the formula: ,where the symbols have usual meanings.

Lakhmir Singh & Manjit Kaur - PhysicsThe speed-time graph of an ascending passenger lift is given alongside.

What is the acceleration of the lift :

(i) During the first two seconds?

(ii) between second and tenth second?

(iii) during the last two seconds?

Lakhmir Singh & Manjit Kaur - PhysicsA car is moving on a straight road with uniform acceleration. The speed of the car varies with time as follows :

Draw the speed-time graph by chooding a convenient scale. From this graph :

(i) Calculate the acceleration of the car.

(ii) Calculate the distance travelled by the car in 10 seconds.

Lakhmir Singh & Manjit Kaur - Physics