A particle starting with certain initial velocity and uniform acceleration covers a distance of 12 m in first 3 s and a distance of 30 m in next 3 s. The initial velocity of the particle is
3 ms-1
2.5 ms-1
1 ms-1
1.5 ms-1
The coordinates of a particle moving in x-y plane at any instant of time t are x = 4t2 ; y = 3t2. The speed of the particle at that instant is
10t
5t
3t
2t
A bullet when fired into a target loses half of its velocity after penetrating 20 cm. Further distance of penetration before it comes to rest is
6.66 cm
3.33 cm
12.5 cm
10 cm
The distance x covered by a particle varies with time t as x2 = 2t2 + 6t + 1. Its acceleration varies with x as
x
x2
x-1
x-3
A particle moving along a straight line covers half of the distance with a speed of 3 ms-1. The other half of the distance is covered in two equal time intervals with speed of 4.5 ms-1 and 7.5 ms-1. The average speed of the particle (in ms-1) is
5.0
5.5
5.8
4.0
Two cars started moving with initial velocities v and 2 v. For the same deceleration, their respective stopping distances are in the ratio
1 : 1
1 : 2
1 : 4
2 : 1
The distances traversed during equal intervals of time by a freely falling body from rest are in the ratio
1 : 3 : 5 : 7 ....
2 : 4 : 6 : 8 .....
1 : 4 : 9 : 25 .....
1 : 9 : 25 : 49 .....
A ball is hung by a string from the ceiling of a car moving on a straight and smooth road. If the string is inclined towards the front side of the car making a small constant angle with the vertical, then the car is moving with
constant velocity
constant acceleration
constant retardation
increasing acceleration
A girl in a swing is 2.5 m above ground at the maximum height and at 1.5 m above the ground at the lowest point. Her maximum velocity in the swing is (g = 10 ms-2)
A car moves a distance of 200 m. It covers first half of the distance at speed 60 kmh-1 and the second half at speed v. If the average speed is 40 kmh-1, the value of v is
30 kmh-1
13 kmh-1
60 kmh-1
40 kmh-1
A.
30 kmh-1
Average velocity =
Given, vav = 40 kmh-1
v1 = 60 kmh-1
and v2 = ?
80 v2 = 2400
v2 = 30 kmh-1