Misconceptions

Q.

Why does the Earth rotate from west to east?

Q.

At which height from earth surface acceleration due to gravity is decreased by 75% of its value at earth surface?

Q. At what height above the earth’s surface the acceleration due to gravity will be 1/9th of its value at the earth’s surface ?

Q.

1. You toss a small ball vertically up in the air. How are the velocity and acceleration vectors of the ball oriented with respect to one another during the ball’s flight up and down?

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. Acceleration due to gravity on earth is g . Find the effective value of acceleration due to gravity at height 32km from sea level
R_e = 6400 km

Q. The acceleration due to gravity of the ball at the highest point, considering downwards as negative, ism/s².

1. \N
2. 9.8
3. -9.8

Q.

എന്താണ് ഭൂഗുരുത്വ ത്വരണം?

Q.

What is the acceleration due to gravity on the top of mouint everest? Mount everest is the highest mountain peak of the world at the height of 8848 m. the value at sea level is $9.80m{s}^{-2}$

Q.

Choose the correct alternative:

(a) Acceleration due to gravity increases/decreases with increasing altitude.

(b) Acceleration due to gravity increases/decreases with increasing depth. (assume the earth to be a sphere of uniform density).

(c) Acceleration due to gravity is independent of mass of the earth/mass of the body.

(d) The formula –G Mm(1/r₂– 1/r₁) is more/less accurate than the formula mg(r₂– r₁) for the difference of potential energy between two points r₂and r₁distance away from the centre of the earth.

Q. Choose the incorrect statements from the following:

1. The escape velocity of a body is independent of the mass of the body and the angle of projection
2. It is possible to shield a body from the gravitational field of another body by using a thick shielding material between them
3. The acceleration due to gravity increases due to the rotational of the earth.
4. The gravitational force exerted by the earth on a body is greater than that exerted by the body on the earth

Q. 31.Acceleration due to gravity on a planet A is 9times than on B.Man jumps from 2m on A.What is corresponding height on B?

Q. Acceleration of block w.r.t wedge if wedge falls with an acceleration a = g is

1. $\frac{g}{\sqrt{3}}$
2. $\frac{g}{2}$
3. $\frac{\sqrt{3}g}{2}$
4. zero

Q. A pendulum bob of mass 50 g is suspended from the ceiling of an elevator. Find the tension in the string if the elevator (a) goes up with acceleration $1.2m/s^2$, (b) goes up with deceleration $1.2m/s^2$, (c) goes up with uniform velocity, (d) goes down with acceleration $1.2m/s^2$, (e) goes down with deceleration $1.2m/s^2$ and (f) goes down with uniform velocity.($g=9.8m/s^2$)

Q. Assertion :When a body dropped from a height explodes in mid-air, its center of mass keeps moving in vertically downward direction. Reason: Explosion occur under internal forces only. External force is zero.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q. Two balls of different masses are thrown vertically upwards with the same speed. They pass through the point of projection in their downward motion (neglecting air resistance)

1. with same momentum.
2. with different speeds.
3. with same speed.
4. information is insufficient.

Q. A simple pendulum having a bob of mass, $m$, is suspended from the ceiling of a car used in a stunt film shooting. The car moves up along an inclined cliff at a speed $v$ and makes a jump to leave the cliff and lands at some distance. Let $R$ be the maximum height of the car from the top of the cliff. The tension in the string when the car is in air is:

1. $mg$
2. $mg+\frac{m{v}^2}{R}$
3. $mg-\frac{m{v}^2}{R}$
4. $zero$