A boat is sent across a river with a velocity of 8 km h-1. If the resultant velocity of boat is 10 km h-1 , then velocity of river is
12.8 km h-1
6 km h-1
8 km h-1
10 km h-1
A body constrained to move in Y-direction is subjected to a force given by . What is the work done by this force in moving the body through a distance of 10 m along Y-axis?
190 J
160 J
150 J
20 J
Two bodies of same mass are projected with the same velocity at an angle 30° and 60° respectively. The ratio of their horizontal ranges will be
1 : 1
1 : 2
1 : 3
1 : √2
A body is whirled in a horizontal circle of radius 20 cm. It has an angular velocity of 10 rad/s. What is its linear velocity at any point on circular path?
√2 m/s
2 m/s
10 m/s
20 m/s
A person swims in a river aiming to reach exactly opposite point on the bank of a river. His speed of swimming is 0.5 m/s at an angle 120° with the direction of flow of water. The speed of water in stream is
1.0 m/s
0.5 m/s
0.25 m/s
0.43 m/s
The angle between the two vectors will be
0°
45°
90°
180°
The vector sum of two forces is perpendicular to their vector differences. In that case, the forces
are not equal to each other in magnitude
cannot be predicted
are equal to each other
are equal to each other in magnitude
When a body moves with a constant speed along a circle
its velocity remains constant
no force acts on it
no work is done on it
no acceleration is produced it
A bullet is fired from a gun with a speed of 100 m/s in order to hit a target 100m away. At what height above the target should the gun be aimed? (The resistance of air is negligible and g = 10 m/s2)
5 cm
10 cm
15 cm
20 cm
A bus is moving on a straight road towards north with a uniform speed of 50 km/h. If the speed remains unchanged after turning through 90°, the increase in the velocity of bus in the turning process is
7.07 km/h along south-west direction
zero
50 km/h along west
70.7 km/h along north-west direction