Misconceptions

Q. A vector has both magnitude and direction. Does it mean that anything that has magnitude and direction is necessarily a vector ? The rotation of a body can be specified by the direction of the axis of rotation, and the angle of rotation about the axis. Does that make any rotation a vector ?

Q. a ball A is thrown vertically up with speed u. at the same instant another ball B is released from rest at a height h vertically above the point of projection of A. taking the moment of projection as t=0 and acceleration due to gravity is g. the time instant at which they collide is? 1. h/u 2. 2h/u 3. root(2h / g) 4. 2h/g

Q. What is the acceleration due to gravity on the top of Mount Everest? Mount Everest is the highest mountain peak of the world at the height of 8848 m. The value at sea level is 9.80 m s⁻².

Q. ge decrease in the acceleration due to gravity when a body is taken from theFind the percesurface of earth to a height of 64 km from its Surface. \lbrack Take R 6.4 x 106 ml2hHint: Use 9.-9

Q. The acceleration due to gravity of the ball at the highest point, considering downwards as negative, is \(~\text{m/s}^2\).

1. \N
2. 9.8
3. -9.8

Q. Two balls are thrown simultaneously in air. The acceleration of the centre of mass of the two balls while in air
(a) depends on the direction of the motion of the balls
(b) depends on the masses of the two balls
(c) depends on the speeds of the two balls
(d) is equal to g.

Q. The acceleration due to gravity of the ball at the highest point, considering downwards as negative, is \(~\text{m/s}^2\).

1. \N
2. 9.8
3. -9.8

Q. Take upwards as positive, when a ball is thrown upwards, the acceleration due to gravity is during the upward motion and during the downward motion.

1. negative
2. negative
3. positive
4. positive

Q. The acceleration due to gravity of the ball at the highest point, considering downwards as negative, is \(~\text{m/s}^2\).

1. \N
2. 9.8
3. -9.8

Q. a particle is projected upwards with initlal velocity u. Assume acceleration due to gravity is 10 m/s2. it is found that the particle covers 5m in last second before reaching the maximum height. What can be the possible value of u?

Q. Can the maximum acceleration in a VERTICAL SHM increase more than acceleration due to gravity? If yes what happens in this case?

Q. A ball is thrown vertically upward. At the highest point of its path, what will be its instantaneous velocity and instantaneous acceleration

Q. A man throws a ball upwards from a tower with an initial velocity u. THEN WHAT SHOULD BE g 9.8 or (-9.8) because object is firstly going upwards & then downwards ? Give reason

Q. Find the acceleration due to gravity in a mine of depth 640 m if the value at the surface is 9.800 m s⁻². The radius of the earth is 6400 km.

Q.

Freely falling bodies can only move downward. T/F why?

Q. Take upwards as positive, when a ball is thrown upwards, the acceleration due to gravity is during the upward motion and during the downward motion.

1. negative
2. negative
3. positive
4. positive