Physics Answers

If the temperature of a hot reservoir is 400K, what must the exhaust temperature be so that the efficiency of an ideal heat engine is 25%?

If all the energy of a 20-g bullet travelling at 1km/s is converted into heat, how many calories are generated?

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A brass rod is 60.04cm at 20ºC. To what temperature must it be raised to make it 60.05cm long?

The Sun has a radius of 6.9599× 10 8 m. Use the mass of the Sun from your data

booklet to calculate the gravitational field strength at the surface of the Sun.

(274 N/kg)

A 10-g rifle bullets requires a speed of a 400 m/s in traversing a barrel 50 cm long. find the average acceleration and acceleration force?

The mechanical power output of a cyclist moving at a constant speed of 5.90 m/s on a level road is 105 W.

By bending low over the handlebars, the cyclist reduces the air resistance to 18.0 N. If she maintains a power output of 105 W, what will her speed be?

1. How far from a convex lens of focal length 25.0 cm must an object be placed to produced an image that is upright and magnified twice?
2. What is the resulting focal length and power if two thin lenses of focal length

+ 25cm and -50 cm are in contact?

The magnitude of the self-induced electromotive force in solenoid is 0.02 V when the current is increasing at a rate of 0.054 A/s

(a) Find the inductance of the solenoid

(b) If the solenoid has 350 turns, what is the magnetic flux through each turn when the current is 0.63 A?

A proton moving horizontally at 3.5 x 10^4m/s enters a uniform magnetic field of 0.075 T directed upward 30° with the horizontal. Find the magnitude of the magnetic force acting on the proton.

a volleyball is spiked so that its incoming velocity of +4.89m/s is changed to an outgoing velocity of -11.7m/s. The mass of the volleyball is 377g. What is the magnitude of the impulse that the player applies to the ball?