Physics Answers

A constant torque of 35 m∙N is applied to a wheel with a moment of inertia of 1.5 kg∙m2. (a) Find the angular acceleration.

(b) Find also the angular speed at the end of 25s, assuming the wheel starts from rest. Show your complete solution.

Eight boys are equally spaced about a pushball and each exerts a force upon it toward the center, as shown. Each boy in positions 1, 3, and 7 exerts a force of 70 N, and the rest of the boys exert 50 N each. What force is needed to keep the ball at rest?

A beam of light passes from water through a thin layer of oil and into air, as shown in the image below. If the incident angle in the water is 20° (the picture is not to scale), at what angle of refraction will the light beam pass from the oil to the air? Show your work and explain your reasoning. The index of refraction of water is 1.33 and the index of refraction of oil is 1.55.

Picture Link: https://ibb.co/JqGYLpj

An immersion electric heater was put in some water and raises it's temperature from 40°c to 100°c in 6 minutes. After another 25 minutes it is noticed that half of the water has boiled away. Neglecting heat losses to the surrounding, calculate the specific latent heat of vaporisation of water.

A boy stands still in a weighing Machine which then read 65kg,he jumps upwards at the instant just before he jumps the machine reads 85kg.what acceleration does he acquire?

Can megnetic fields exist independently of electric charges? 

A bullet of mass 0.05kg travelling horizontally at 30ms^-1 embeds itself in wooden block of mass 0.95kg.if the block is suspended by a light vertical string 1m long calculate the maximum inclination of the string at the horizontal

An apple is falling down from a height of 20m and then hit a

person. Assume that the mass of the apple is 200g. The

duration of impact is 0.001 sec and that the area of the

bone is 1 cm(square). (a) Calculate the impulsive force applied to

the person. (b) If the rupture strength for body tissue is

about 5 X 1000000dyn/cm(sqare), will the impact force lead to serious

injury for the person?

A lead bullet of mass 50g is fired with velocity 300ms^-1 into a lead block of mass 0.75kg, given that the lead block can move freely, calculate the combine speed of the bullet and the block after the impact

In a car collision, the bag expands suddenly and cushions

the impact of the passenger. Assume the impact velocity is

105 km/h. For a 70-kg person with a 30-cm allowed

stopping distance, (a) calculate the stopping force per cm(square)

applied to the person, if the average applied force is

uniformly distributed over a 1000-cm(square) area of the

passenger's body. (b) calculate the duration of the collision

between the passenger and the inflated bag of the collision

protection device. (c) If the rupture strength for body tissue

is about 5 X 1000000 dyn/cm(sqare), will the impact force lead to

serious injury for the passenger?