CBSE
Multiple Choice QuestionsA ball is dropped from the top of a building 100 m high. At the same instant another ball is thrown upwards with a velocity of 40 m/s from the bottom of the building. The two balls will meet after
3 s
2 s
2.5 s
5 s
The displacement of a body is given to be proportional to the cube of time elapsed. The magnitude of the acceleration of the body is proportional to
t
t2
t3/2
Water is flowing with velocity 4 m s-1 in a cylinder of diameter 8 cm, it is connected to a pipe with it end tip of diameter 2 cm, calculate the velocity of water at this free end.
4 m s-1
8 m s-1
32 m s-1
64 m s-1
A particle is moving eastwards with a velocity of 5 m/s. In 10 s, the velocity changes to 5 m/s northwards. The average acceleration in this time is
zero
1/√2 m s-2 towards north-west
1/√2 m s-2 towards north-east
1/√2 m s-2 towards north
A particle is thrown vertically upwards with velocity 11.2 km s1 from the surface of earth. Calculate its velocity at height 3 R. Where R is the radius of earth
9.25 km s-1
5.6 km s-1
11.2 km s-1
4.3 km s-1
Assertion: The relative velocity between any two bodies moving in opposite direction is equal to sum of the velocities of two bodies.
Reason: Sometimes relative velocity between two bodies is equal to difference in velocities of the two bodies.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
If a vector is perpendicular to the vector , then value of α is
-1
1
A man is at a distance of 6 m from a bus. The bus begins to move with a constant acceleration of 3ms.In order to catch the bus, the minimum speed with which the man should run towards the bus is
2 m s-1
4 m s-1
6 m s-1
8 m s-1
Assertion: If α = - 2t for a particle moving in a straight line starting with initial velocity 4 m/s from the origin, then distance travelled by it in 2 s is same as displacement.
Reason: Velocity changes direction after 2 s only.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
Assertion: The speedometer of an automobile measures the average speed of the automobile.
Reason: Average velocity is equal to total distance divided by total time taken.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false.
If both assertion and reason are false.
