The position vector of a particle, is . The velocity of the particle is
directed towards the origin
directed away from the origin
parallel to the position vector
perpendicular to the position vector
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
The vectors and are such that | + | = | - | then angle between the two vectors will be
45°
60°
75°
90°
The angle between and is θ. The value of the triple product .( × ) is
A2B
zero
A2B sin θ
A2B cos θ
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
50 km/h along west
70.7 km/h along north-west direction
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
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
The magnitudes of vectors are 3,4 and 5 units respectively. If , the angle between is
cos-1 (0.6)
The resultant of × 0 will be equal to
A
zero vector
unit vector
An electric fan has blades of length 30 cm measured from the axis of rotation. If the fan is rotating at 120 rev/min, the acceleration of a point on the tip of the blade is
1600 ms-2
47.4 ms-2
23.7 ms-2
50.55 ms-2
