A man is walking on a horizontal road at a speed of \(4~\text{km/hr}.\) Suddenly, the rain starts vertically downwards with a speed of \(7~\text{km/hr}.\) The magnitude of the relative velocity of the rain with respect to the man is:
1. \(\sqrt{33}~\text{km/hr}\)
2. \(\sqrt{65}~\text{km/hr}\)
3. \(8~\text{km/hr}\)
4. \(4~\text{km/hr}\)
A particle of mass 6 kg moves with an initial velocity of m/s. A constant force of N is applied to the particle. Initially, the particle was at (0, 0). The x-coordinate of the particle, when its y-coordinate again becomes zero is given by
(1) 6.0 m
(2) 12.8 m
(3) 8 m
(4) 25.6 m
In a uniform circular motion:
(1) Velocity and acceleration remain constant.
(2) Kinetic energy remains constant.
(3) Speed and acceleration changes.
(4) Only velocity changes, acceleration remains constant.
If a body is accelerating, then:
1. | it must speed up. |
2. | it may move at the same speed. |
3. | it may move with the same velocity. |
4. | it must slow down. |
Compared to an ideal projectile motion under gravity, which of the following is incorrect regarding another projectile motion in which air friction is also considered?
1. | The time of flight decreases. |
2. | Decrease in the horizontal component of velocity continuously. |
3. | The angle with horizontal is less at the time of striking the ground compared to the angle of projection with horizontal. |
4. | The angle with the vertical is less at the time of striking the ground with respect to the angle of projection with vertical. |
Two balls are projected to acquire same range with the same initial speed u but at different angles of projection. If maximum height acquired by balls are , then () is: (angle of projection of one projectile is )
(1)
(2)
(3)
(4) tan
At the highest point of trajectory in the ground to the ground projectile, the angle between gravitational acceleration and momentum is
(1) 30°
(2) 45°
(3) 90°
(4) Data insufficient
A particle revolves in a horizontal circle with decreasing velocity. The angle between instantaneous velocity and instantaneous acceleration of the particle at an instant is
(1) < 90°
(2) > 90°
(3) = 90°
(4) 90°
Two projectiles are thrown horizontally from a high cliff in the opposite direction with the same speed 20 m/ s simultaneously. At what time velocities of both particles become perpendicular?
(1) 2 s
(2) 2 s
(3) 4 s
(4) 4 s