Physics Answers

A stone projected horizontally from the top of a tower with a speed of 5m/s. It lands on the ground level of the horizontal distance of 20m from the top of the tower. Calculate the height of the tower. g= 10m/s²

A car is traveling at a speed of 33 m/s. (a) What is its speed in kilometers per hour? (b) Is it exceeding the 90 km/h speed limit?

A beach ball is rolling in a straight line toward you at a speed of 0.5 m/s. Its momentum is 0.25 kg*m/s.

What is the mass of the beach ball?

Two point charges are placed as follows: charge q1 = -1.50 nC is at y = +6.00 m and charge q2 = +3.20 nC is at the origin. What is the total force (magnitude and direction) exerted by these two charges on a negative point charge q3 = -5.00 nC located at (2.00 m, -4.00 m)? 

A gardener pushes a lawnmower of mass 18kg at a constant speed. To do this requires a force P of 80N directed along the handle, which is at an angle of 40°to the horizontal.

a) Calculate the horizontal frictional force

b) If this frictional force were constant, what force, applied along the handle, would accelerate the mower from rest to 1.2m/s in 2.0s?

the erth is on average 150 million kilometers from the sun calculate it's average speed in orbit?

4. A constant force of 45N acts on a 15 kg box. The direction of the force is to the left. If the box is originally at rest, what will be its velocity after 5s? Indicate the magnitude and direction of the velocity.

A rechargeable battery has "emf_{\u03b5battery}""=14.0V", internal resistance "r=4.00\\Omega" and battery capacity (total charge) "2.00 Ah".

When the battery is fully charged, a light bulb is connected to it for 8 hours (see picture above). The light bulb has specs "14.00V" and "1.00W". We assume the light bulb has constant resistance (independent of the current) and the emf of the battery remains constant.

After these 8 hours the battery is disconnected from the light bulb and connected in this circuit for charging:

The charger consists of a ideal voltage source with "emf_\u03b5=20.0 V"  (with no internal resistance) and a resistor "R_1"  in series.

(a) What is the minimum time that is needed to fully recharge the battery (with "R_1=0\\Omega")

(b) What should the resistance "R_1"  be to fully recharge the battery in exactly 1 hour?

Three indistinguishable particles are to be distributed in two cells. Find possible number of

macrostates and corresponding number of microstates.

A parallel plate capacitor is charged to 100v.its plate separation is 2mm and the area of separation of each plate is 120cm^2.calculate and account for the increase and decrease in energy when separation is reduced to 1mm at constant voltage and charge