Physics Answers

What is quantity of motion?

A projectile is fired at an angle 15 ° from a gun that is 45 m above the flat ground, emerging

from the gun with a speed of 300 m/s.

(a) How long does the projectile remain in air?

(b) At what horizontal distance from the firing ground does it strike the ground.

(c) What is the velocity of the projectile when it hits the ground?

For the vectors 𝑟⃗1 = 2𝑖̂− 3 𝑗̂+ 4𝑘̂ 𝑎𝑛𝑑 𝑟2̂ = 4𝑖̂+ 2𝑘̂

(a) Find the angle between them.

(b) Find the cross-product of the vectors.

A rock is dropped from a 300 m –high cliff. How long does it take to fall (a) the first 100 m

and (b) the last 50 m.

A wet socks clinging to the inside of a washing machine drum which is spinning at a speed of

4.7 m/s. The radius of the drum is 30 cm. What is the minimum coefficient of static friction

between sock and the drum so that the sock will not slip down?

A projectile is fired horizontally at a speed of 8 m/s from an 80-m-high cliff. Find (a) The velocity just before the projectile hits the ground.

a bullet of mass 0.100f is moving horizontally with a momentum of 0.0980kg m/s. express this momentum in g cm/s

The equivalent resistance of two resistors R1 and R2 is given by 𝑅𝑒𝑞 = 𝑅1 + 𝑅2 and 𝑅𝑒𝑞 =

𝑅1𝑅2

𝑅1+𝑅2

when they are connected in series and parallel respectively. If 𝑅1 = 22.0 Ω ±

5% 𝑎𝑛𝑑 𝑅2 = 47.0 ± 5% , find the maximum error in the calculation of their equivalent

resistance when they are connected in series and parallel.

DETERMINE THE RESISTANCE OF A BUSBAR MADE OF COPPER IF THE LENGTH IS 5m LONG

AND THE CROSS-SECTION IS A 4X4𝑐m^2 . USE 1.7241 MICRO OHM-CM.

A rope 5m long is fastened to two hooks 4m apart on a horizontal ceiling to the rope is attached a 10kg mass so that the segment of the rope is 3m and 2m. Compute the tension in each segment