A person of mass 74 kg stands at the center of a rotating merry-go-round platform of radius 3.5 m and moment of inertia 880 kg⋅m2 . The platform rotates without friction with angular velocity 0.90 rad/s . The person walks radially to the edge of the platform.

Calculate the angular velocity when the person reaches the edge.

Calculate the rotational kinetic energy of the system of platform plus person before and after the person's walk.

On a frictionless horizontal air table, puck A (with mass 0.245 kg ) is moving toward puck B (with mass 0.374 kg ), which is initially at rest. After the collision, puck A has velocity 0.118 m/s to the left, and puck B has velocity 0.655 m/s to the right.

A: What was the speed vAi of puck A before the collision?

B: Calculate ΔKΔKDeltaK, the change in the total kinetic energy of the system that occurs during the collision.

A cannonball is fired at a cliff of height h with an initial speed of v0 = 42.0 m/s directed at an angle of θ = 60.0° above the horizontal. The cannonball strikes point A precisely 5.50 s after it is launched. Ignore air resistance. a) Find the maximum height the cannonball reaches, H. b) Find the height of the cliff, h. c) Find the velocity of the cannonball the instant before it strikes point A. Give your answer in unit vector notation.

Paul has a margin account with a balance of ¢150,000. The initial margin deposit is 60 percent and Choco Industries is currently selling at ¢50 per share. a. How many shares of Choco can Paul purchase? b. What is Paul's profit/loss if Choco's price after one year is ¢40? c. If the maintenance margin is 25 percent, to what price can Choco Industries fall before Paul receives a margin call?

Assume you mix (1.25x10^2) mL of 0.400 M HCl with the same volume of 0.400 M NaOH in a coffee-cup calorimeter (as will be done in the lab). The temperature of the solution before the mixing was 25.10 deg. C; after mixing and allowing the reaction to occur, the temperature is 27.78 Deg. C. What is the enthalpy of neutralization of the acid. Assume the densities of all the solutions are 1.00 g/mL and their specific heat capacities are 4.18 J/(g*K)

A battery is constructed based on the oxidation of magnesium and the reduction of Cu2+. The initial concentrations of Mg2+ and Cu2+ are 1.2×10⁻⁴ M and 1.5 M , respectively, in 1.0-liter half-cells.

A)What is the initial voltage of the battery?   

B)What is the voltage of the battery after delivering 5.0 A for 8.0 h ?

C) What are the concentrations of Mg²⁺ and Cu²⁺ when the cell is dead?

D)  How long can the battery deliver 5.0 A before going dead?

Experimental Design and Statistics Question

If our dataset included 100 possible explanatory variables, we would expect to see statistical significance for 5 comparisons, by chance alone. (That is 5%, after all, and we have set our alpha value at 5%!) Given this, explain why it is important to clearly state your null hypothesis, plan your study design, and draw your predicted results before you conduct your experiment.

Technological innovations in oil drilling have decreased the cost of producing propane gas.

a. Show this change graphically in a supply and demand diagram for propane. Clearly label your curves and equilibrium price and quantity both before and after the change in technology

.b. If the demand for propane increases significantly during the summer as more people grill outside, what will be the net impact of this change in demand combined with the change from (a) on market equilibrium price and quantity of propane?

The general fund of the Village of Beantown borrowed $100,000 on July 15, 2019, from the local bank in order to pay for government services provided to its citizens before the first collection of its property tax levy. After collecting the first property tax installment, Beantown paid the local bank $102,000 on September 12, 2019.

Required:

Make the village’s general fund journal entry to record the payment to the bank on September 12