Physics Answers

Assume that the temperature effects of glaciations can be

represented by a periodic surface temperature with a period of 104 yr. If

it is desired to drill a hole to a depth that the temperature effect of the

glaciations is 5% of the surface value, how deep must the hole be drilled?

Assume κ = 1 mm2 s−1.

30N and 46N forces are perpendicular to each other and pull a single object what is the third force that must act on the object if the result is 0

The period T of a simple pendulum is assumed to be affected by the following quantities.1 mass of bulb m 2 length of pendulum l 3 acceleration due to gravity g

if the empirical formula for the period T is T =Kmlg .find the relationship between T and the products of these two quantities using dimensional analysis

A particle of mass m is attached to the end of a string and moves in a circle of radius of radius r on a frictionless horizontal table. The string passes through a frictionless hole in the table and, initially, the other end id fixed. a) if the string is pulled so that the radius of the circular orbit decreases, how does the angular velocity change if it is ω0 when r = r0? b) what work is done when the particle is pulled slowly in from a radius r0 to a radius r0/2? 

A flywheel of rotational inertia I = 53kg⋅m2 rotates with angular speed 4.0 rad/s. A tangential force of 6.5 N is applied at a distance of 0.36 m from the center in such a way that the angular speed decreases. How long will it take the wheel to stop?

Result: 100 s

A stationary tyre begins to rotate at constant angular acceleration to reach an angular velocity of 12.0 rad/s in 3.00 s. Find (a) the magnitude of the angular acceleration of the tyre and (b) the angle in radians that it rotates during this time interval.

Result: (a) 4.00 rad/s2 (b) 18.0 rad

A 7-kg rifle is used to fire a 10-g bullet that travels with a speed of 700 m/s. (a) What is the speed of recoil of the rifle? (b) How much energy does it transmit to the shoulder of the person using the rifle as it stops?

Result: (a) -1.0 m/s (b) 35 J

A meter rule is pivoted at its mid point c with a vertical force of 10N hanging from the distance 30cm from c at what distance must a15N force hang to balance the ruler horizontally

i.                   For transverse waves on a string, is the wave speed the same as the speed of any part of the string? Explain the difference between these two speeds. Which one is constant? Which has a more direct influence on the loudness of a sound wave: the displacement amplitude or the pressure amplitude? Explain your reasoning.

ii.                 A sound source and a listener are both at rest on the earth, but a strong wind is blowing front the source toward the listener. Is there a Doppler effect? Why or why not?

iii.               When you use a hand pump to inflate the tires of your bicycle, the pump gets warm after a while. Why? What happens to the temperature of the air in the pump as you compress it? Why does this happen? When you raise the pump handle to draw outside air into the pump, what happens to the temperature of the air taken in? Again, why does this happen?

iv.               Suppose the two plates of a capacitor have different areas. When the capacitor is charged by connecting it to a battery. do the charges on the two plates have equal magnitude. Or may they be different? Explain your reasoning.

You connect a number of identical light bulbs to a flashlight battery. (a) What happens to the brightness of each bulb as more and more bulbs are added to the circuit if you connect them (i) in series and (ii) in parallel? (b) Will the battery last longer if the bulbs are in series or in parallel? Explain your reasoning