Physics (For 1st SEC.) Mr. Sabry Badr

If the tangential velocity of a body that undergoes a uniform circular motion is doubled and the radius of the circular path is increase four times, the centripetal acceleration ............

• gets halved

• gets quadrupled

• gets doubled

• remains unchanged

A man of mass 70 kg rides a bicycle on a curved road of radius  20 m with a speed of  2 m/s. If the centripetal force that acts on both the man and the bicycle is 20 N, so the mass of the bicycle is ....... kg

• 20

• 25

• 30

• 100

Two balls have the same mass, so if the distance between their centers is 4 m and the attraction force between them is  11.8 x 10^-9 N, the mass of each ball equals........ kg         (Take: G=6.67x 10^-11 N.m²/kg²)

• 43.4

• 50

• 53.2

• 56

If the distance between the centers of two bodies decrease to half, the mutual attraction force between them will be .........

• doubled

• halved

• quartered

• quadrupled

If the acceleration due to gravity on the surface of the Earth = 9.8 m/s²  and on Mars = 3.7 m/s², so the ratio between the gravitational constant on Earth and that on Mars = ...............

An object weighs 200 N on the Earth's surface, so the weight of this object on a planet having a mass that is 2 times as that of Earth and having a diameter that is 4 times as that of the Earth equals.......  N

• 25

• 50

• 100

• 1600

A body of mass 4 kg moves in a circle of circumference 20 π   m with a constant speed of  20 m/s, so the centripetal force that acts on the body is .......... N

• 100

• 160

• 1000

• 1600

A plant has a mass = 3.4 x 10²⁰ Kg and radius 5900 Km, So the intensity of the gravitational field at point lies at a distance of 2600 Km from it = ........................ m/s²

• 4.5 x 10^{- 4}

• 3.13 x 10^{- 4}

• 8 x 10⁴

• 2.5 x 10⁴

A body weight 60 N at the Earth’s surface, So its weight at height from the Earth’s surface that equal the quarter of the Earth’s diameter = ................. N

• 26.6

• 40.2

• 120

• 1.2