Physics Answers

Suppose we are told that the acceleration (a) of a particle moving with uniform speed (v)

in a circle of radius (r) is a=kr^ n v^ prime

Determine the values of n and m and write the simplest form of this equation.

Note: K is a dimensionless constant

"Show your work"

An object hits the ground travelling at 40 ms-1 . It is brought to rest in 0.02 s . What is its acceleration ?

A solar collector for a hot water system absorbs solar radiation at the rate of 660 W/m Its collecting area is 3.8 m². Cold water at 15°C enters the collector. What volume of water per minute at an output temperature of 60°C can this collector deliver?

A polytropic process of air from 1034 kPa, 149 deg. C and 0.028 m3 occurs to 138 kPa in accordance with pV1.3 = C. Determine

(a) the final temperature in deg. C

(b) the change in internal energy in kJ

(c) the work nonflow in kJ

(d) the heat in kJ from the formula using polytropic specific heat

A man lifts a mass of 3kg upwards through 2m. If g=10m/s2 calculate work done

Two fixed charges 1.07 micro Coulomb and -3.29micro Coulomb are 61.8cm apart where may a third charge be located so that no net force act on it?

need better explantion please

A man stands on a freely rotating platform. With his arms extended, his rotation frequency is 0.25 rev/s. But when he draws them in, his frequency is 0.8 rev/s. Find the ratio of his moment of inertia in the first case to that of the second.

The force due to weight of a certain flywheel is 5000 lb, having a radius of gyration of 3 ft. If there is a a driving torque of 600 lb - ft and a resisting torque of 250 lb - ft, find the time to increase its speed from 20 rev/min to 80 rev/min. (Hint : The moment of inertia is directly proportional to the square of radius of gyration, having the constant of proportionality to be the mass of the system.)

A certain flywheel is acted upon by a constant torque of 45 N-m. Find the time it takes to go from rest to an angular velocity of 812 rev/min if the moment of inertia is 5 kg-m2?

A block of cherry wood that is 20.0 cm long, 10.0 cm wide, and 2.00 cm thick has a density of 800. kg/m3. What is the volume of a piece of iron that, if glued to the bottom of the block, makes the block float in water with its top just at the surface of the water? The density of iron is 7860 kg/m3, and the density of water is 1000. kg/m3.