A motor car covers part of total distance with = 10 km/hr, second part with = 20 km/hr and rest part with = 60 km/hr. What is the average speed of the car?
1. 18 km/hr
2. 45 km/hr
3. 6 km/hr
4. 22.5 km/hr
The adjoining curve represents the velocity-time graph of a particle, its acceleration values along with OA, AB, and BC in are respectively-
1. 1, 0, -0.5
2. 1, 0, 0.5
3. 1, 1, 0.5
4. 1, 0.5, 0
A ball is dropped from a certain height on a glass floor so that it rebounds elastically to the same height. If the process continues, the velocity-time graph for such a motion would be -
(i) | (ii) |
(iii) | (iv) |
1. (i)
2. (ii)
3. (iii)
4. (iv)
A particle, after starting from rest, experiences constant acceleration. If it covers a distance of in the first 10 seconds and distance in the next 10 sec, then-
1.
2. =
3. = 2
4. 3 =
A particle moves with constant speed v along a regular hexagon ABCDEF in the same order (i.e. A to B, B, to C, C to D, D to E, E to F, F to A....). Then the magnitude of average velocity for its motion from A to C is -
1. v
2. v/2
3. v/2
4. None of these
A person is moving in a circle of radius r with constant speed v. The change in velocity in moving from A to B is-
1. \(2 v~ cos ~40^\circ\)
2. \(2 v~ sin ~40^\circ\)
3. \(2 v~ cos ~20^\circ\)
4. \(2 v~ sin ~40^\circ\)
A train accelerates from rest at a constant rate for distance and time . After that retards rest at to constant rate β for distance in time and comes to the rest, which of the following relation is correct -
(1)
(2)
(3)
(4)
A disc in which several grooves are cut along the chord drawn from a point 'A', is arranged in a vertical plane, several particles start slipping from 'A' along the grooves simultaneously. Assuming friction and resistance negligible, the time taken in reaching the edge of disc will be-
1. | Maximum in groove AB |
2. | Maximum in groove AD |
3. | Same in all groove |
4. | According to the height of B, C, D, E, F |
A stone is dropped into a well in which the level of water is h below the top of the well. If v is velocity of sound, the time T after which the splash is heard is given by -
(1) T =
(2) T =
(3) T =
(4) T =
A body is dropped from the top of a tower covers of total height in the last second of its fall. The time of fall is -
1. 2 s
2. 4 s
3. < 1 s
4. > 5 s
A particle moving in a straight line covers half the distance with a speed of 3 m/s. The other half of hte distance is covered in two equal time intervals with speed of 4.5 m/s and 7.5 m/s respectively. The average speed of the particle during this motion is-
1. 4.0 m/s
2. 5.0 m/s
3. 5.5 m/s
4. 4.8 m/s
The deceleration experienced by a moving motor boat, after its engine is cut off is given by , where k is constant. If is the magnitude of the velocity at cut off, the magnitude of the velocity at a time t after the cut-off is-
(1)
(2)
(3)
(4)
The displacement of a particle is given by . The initial velocity and acceleration are respectively-
1. b, -4d
2. -b, 2c
3. b, 2c
4. 2c, -4d
The graph between the displacement x and time t for a particle moving in a straight line is shown in figure. During the interval OA, AB, BC and CD, the acceleration of the particle is-
.
OA AB BC CD
(1) + 0 + +
(2) − 0 0 +
(3) + 0 − 0
(4) − 0 − 0
A particle moves along a straight line OX. At a time t(in seconds) the distance x (in metres) of the particle from O is given by x = 40 + 12t - . How long would the particle travel before coming to rest-
1. 24 m
2. 40 m
3. 56 m
4. 16 m
A particle is moving along x-axis has acceleration f, at time t, given by , where and T are constants. The particle at t = 0 has zero velocity. In the time interval between t = 0 and the instant when f = 0, the particle velocity is-
1.
2.
3.
4.
A bus is moving with a speed of 10 m/s on a straight road. A scooterist wishes to overtake the bus in 100 s. If the bus is at a distance of 1 km from the scooterist, with what speed should the scooterist chase the bus-
1. 10 m/s
2. 20 m/s
3. 40 m/s
4. 25 m/s
The motion of a particle along a straight line is described by an equation where x is in metre and t is in second. The retardation of the particle when its velocity becomes zero is:
1. 6
2. 12
3. 24
4. zero
A particle of unit mass undergoes one-dimensional motion such that its velocity varies according to where and n are constants and x is the position of the particle. The acceleration of the particle as a function of x, is given by:
1.
2.
3.
4.
If the velocity of a particle is v=At+Bt, where A and B are constants, then the distance travelled by it between 1s and 2s is :
(1) 3A+7B
(2)
(3)
(4)
Two cars P and Q start from a point at the same time in a straight line and their positions are represented by (t)=at+bt and (t)= ft− . At what time do the cars have the same velocity ?
(1)
(2)
(3)
(4)