A. Starting from the assumption that angular momentum is conserved, prove Kepler's second law, the constancy of areal velocity.

B. Starting from Kepler's first and second laws and Newton's Universal Law of Gravity, prove Kepler's third law (The Harmonic Law).

A combination lock has a 1.3-cm-diameter knob that is part of the dial you turn to unlock the lock. To turn that knob, you grip it between your thumb and forefinger with a force of 4.0 N as you twist your wrist. Suppose the coefficient of static friction between the knob and your fingers is  0.75.

A)What is the most torque you can exert on the knob without having it slip between your fingers?

how is chiropractics related to physics, through formulas and explanation.

Using physics equations, explain why thicker guitar strings make lower notes than thinner guitar strings.

1. Write the standard momentum equation for one train car colliding and hooking with another immobile train car if both cars have a mass of M: What type of collision?

2. If the second car was to jump ahead and the two didn’t connect together what would be the new equation? What type of collision?

C. If the mass of each car is 7000kg and the final velocity of the trains after collision is 2m/s. Then solve the equation described above.

   D. Solve the equation described in part b with the same data as in part C if the mobile train car was moving at 28m/s before collision and continues on after collision at 7m/s. What is the kinetic energy before collision and After collision? Is it conserved?

Renewable sources of energy include photovoltaic, solar thermal electric, wind, geothermal, and hydroelectric. of these five types of energy, which one shows the greatest promise for economic viability over the next 10 years. why do you say this, and what obstacles, if any must be overcome to make this a reality?

what effect will a 0.20 g error (reading is 0.20g lower than the actual value) in reading the amount of Cu in this calorimetry experiment have on determining the specific heat?

A solenoid that is 91.4 cm long has a cross-sectional area of 24.8 cm². There are 811 turns of wire carrying a current of 8.08 A. (a) Calculate the energy density of the magnetic field inside the solenoid. (b) Find the total energy in joules stored in the magnetic field there (neglect end effects).

A 74 kg soccer player jumps vertically upwards and heads the 0.45 kg ball as it is descending vertically with a speed of 26 m/s. If the player was moving upward with a speed of 4.0 m/s just before impact, what will be the speed of the ball immediately after the collision if the ball rebounds vertically upwards and the collision is elastic?
If the ball is in contact with the player's head for 20 ms, what is the average acceleration of the ball? (Note that the force of gravity may be ignored during the brief collision time.)

How are the latent and manifest images made in computed radiography?

A person is riding a bicycle, and its wheels have an angular velocity of 22.0 rad/s. Then, the brakes are applied and the bike is brought to a uniform stop. During braking, the angular displacement of each wheel is 12.9 revolutions. (a) How much time does it take for the bike to come to rest? (b) What is the anguar acceleration (in rad/s2) of each wheel?

A window washer with a mass of 63.0 kg stands a distance, D = 0.600 m, from the left end of a plank of length, L= 2.10 m, with a mass of 19.0 kg. The plank is hung on two cables as shown. Find T₂, the tension in the right cable.

A geosynchronous communications satellite in stationary orbit is used to relay radio messages from one point to another around the earth’s curved surface. Apply Newton’s second law to the satellite to find its altitude in meters above the earth’s surface. R_E = 6.38 × 10⁶ m, m_E = 5.97 × 10²⁴ kg, and G = 6.674 × 10⁻¹¹ Nm²/kg².

Q1. A hand grenade of total mass 5kg explodes into three pieces. Two of them, each of mass 1kg, have velocities of 8m/s with an angle of 43° between them. What is the speed of the third piece?

**well the answer should be 3.9 m/s as per my HW, I just kept getting It wrong, kindly show how to solve for this answer.

Q2. is similar

a hand grenade has a mass of 6kg and It explodes into 3 pieces each of the same mass. two of them go off, each with a speed of 17 m/s with an angle of 60 degrees between their trajectories. what is the speed of the third?

the answer should be 29.4 (as per my homework) I just don't know how to solve It.

determine the potential energy stored in a spring if a force of 28 holds the spring and it has a spring constant of 97 N/m compressed.

please answer in joules and explain how you solved It. (like dumb it down) so that I could learn. thank you!