A motorboat covers a given distance in 6 h moving downstream on a river. It covers the same distance in 10 h moving upstream. The time it takes to cover the same distance in still water is
9 h
7.5 h
6.5 h
8 h
The displacement-time graph of two moving particles make angles of 30° and 45° with the X-axis. The ratio of their velocities is
1 : 1
1 : 2
In a lift moving up with an acceleration of 5ms-2 dropped from a height of 1.25 m. The time taken by the ball to reach the floor of the lift is (g = 10 ms-2)
0.3 s
0.2 s
0.16 s
0.4 s
D.
0.4 s
Distance travelled by ball during fall = 1.25 m
By using the relation,
A car moves from A to B with a speed of 30 km/h and from B to A with a speed of 20 km/h. What is the average speed of the car ?
25 km/h
24 km/h
50 km/h
10 km/h
A body starts from rest and moves with constant acceleration for t sec. It travels a distance x1 in first half of time and x2 in next half of time, then
x2 = x1
x2 = 2x1
x2 = 3x1
x2 = 4x1
The velocity-time graph for two bodies A and B are shown in figure. Then, the acceleration of Aand B are in the ratio
sin 25° to sin 50°
tan 25° to tan 40°
cos 25° to cos 50°
tan 25° to tan 50°
A body falls freely for 10 s. Its average velocity during this journey is (Take, g = 10 ms-2)
100 ms-1
10 ms-1
50 ms-1
5 ms-1
From the top of a tower a stone is thrown up which reaches the ground in a time t1. A second stone thrown down with the same speed reaches the ground in a time t2. A third stone released from rest from the same between reaches the ground in a time t3. Then