Physics Answers

A foam cup is filled with a hot water and allowed to cool while being stirred by a paddlewheel.

initially, the water has an internal energy of 200kj,and while cooling it loses 150kj of heat.

the paddlewheel does 25kj of work on water

a) calculate the change in internal energy of water

b) calculate the final internal energy of water

Normalize wave function psi where psi(x) = {e^-ax for x>0 e^ax for x<0

A circuit has a resistor with a resistance of 3Ω followed by three parallel branches, each holding a resistor with a resistance of 5Ω. What is the total equivalent resitance of the

circuit?

Find the voltage drop in an extension cord having a 0.0600 Ω resistance and through which 5.00 A is flowing.

A wave out in the deep ocean has an amplitude of 1.51 m, a wavelength of 212 m and a period of 14.3 s

What is the speed of such a wave? (in m s⁻¹ to 3 s.f)

A small toy gun fires light foam projectiles by compressing a spring. As the spring relaxes it pushes the projectile.

The toy gun has a spring with a spring constant of 484 N m−1, the spring is compressed by 5.00 cm, and it fires a 10.0 g projectile.

At what speed does the projectile leave the toy gun? (in m s−1 to 3 s.f)

A runaway 185 kg wheeled skip is rolling east along a road with a velocity of +2.2 m s−1. A 2560 kg car moving to the west with a velocity of −9.7 m s−1 hits the skip.

After the collision the skip is moving west with a velocity of −14.4 m s−1.

What is the velocity of the car after the collision? (in m s−1 to 2 s.f)

A person throws a 755 g ball up at an angle such that it has an initial speed of 15.0 m s−1. After a short time the ball has a speed of 5.30 m s−1.

How much higher is the ball than when it was let go? (in m to 3 s.f)

(note: use g = 9.81 m s−2)

A person is riding in a car which is moving at a constant speed around a circular arc.

The person has an accelerometer on their mobile phone and uses it to measure a lateral (horizontal) acceleration of 5.6 m s−2.

If the car was traveling at 50 km h−1 (14 m s−1) then what was the radius of the curve that car was traveling along? (to 2 s.f)

A 64.0 kg person is riding an elevator as shown in the figure above. The elevator is accelerating upwards at a rate of 0.682 m s−2.

For this problem use g = 9.81 m s−2

What is the magnitude of the normal force, the force on the person from the elevator? (in N to 3.s.f)