If the position of a particle varies according to the equations x = 3, y = 2t, and z = 4t + 4, then which of the following is incorrect?
1. | Velocities in y and z directions are constant |
2. | Acceleration in the x-direction is non-uniform |
3. | Acceleration in the x-direction is uniform |
4. | Motion is not in a straight line |
If three coordinates of a particle change according to the equations , then the magnitude of the velocity of the particle at time \(t=1\) second will be:
1. unit
2. unit
3. \(40\) unit
4. unit
Two bodies of equal masses are projected, one from top of the tower in the horizontal direction and other from the foot of tower at an angle of 45° with the horizontal, then the acceleration of their center of mass is
(1) downward
(2) g downward
(3) downward
(4) upward
A projectile is projected at an angle of 60° from horizontal. At an instant, it is moving at an angle of 30° with horizontal with velocity 10 m/s. The radial acceleration of the particle at that instant is:
1.
2.
3.
4.
The initial velocity of a projectile is given by m/s. If acceleration due to gravity is g = 10() m/, then the time after which projectile returns to the same horizontal level is:
(1) 4 s
(2) 10 s
(3) 14 s
(4) 12 s
Two persons start moving along two crossroads with the same speed 5 m/s. One in the direction of north and other is in the direction of the east as shown in the figure. Angular velocity of A with respect to B is :
(1) 0.5 m/s
(2) Zero
(3) 1.0 m/s
(4) 2 m/s
In projectile motion, accelerations of the projectile when it is gaining height and losing height respectively are
(1) g upward, g upward
(2) g upward, g downward
(3) g downward, g downward
(4) g downward, g upward
A person, who can swim with speed u relative to water, wants to cross a river (of width d and water is flowing with speed v). The minimum time in which the person can do so is:
1.
2.
3.
4.
The position vector of a particle as a function of time t (in seconds) is . The initial acceleration of the particle is:
1. 2
2. 3
3. 4
4. Zero
A particle is projected on a horizontal surface with kinetic energy K at an angle with the vertical. The kinetic energy of the particle at the highest point of trajectory is:
(1) K
(2) Zero
(3) K
(4) K