# Physics Midterm Help!

*label*Science

*timer*Asked: Aug 28th, 2015

*account_balance_wallet*$15

**Question description**

**Midterm**

If a freely falling rock were equipped with a speedometer, by how much would its speed readings increase with each second IF it were on a planet where g = 20 m/s2? Show all work leading to your answer.

An airplane has a gun that fires bullets straight ahead at the speed of 600 miles per hour when tested on the ground while the plane is stationary. The plane takes off and flies east at 600 miles per hour. Explain whether each of the following is possible for the pilot to measure:

When fired directly ahead the bullets move eastward at a speed of 1200 miles per hour

When fired in the opposite direction (by turning the gun westward, but not the plane), the bullets drop vertically downward

If fired vertically downward (by turning the gun downward, but not the plane), the bullets move eastward at 600 miles per hour while they fall.

A falling 50-kg skydiver experiences an upward acceleration of 6.2 m/s2 when she opens her parachute. Show (by calculation) how much drag force is produced by the parachute.

Leon’s bicycle wheels have a circumference of 2 m. What is his linear speed when the wheels rotate at 1 revolution per second? Show all work leading to your answer.

At a particular point, a satellite in an elliptical orbit has a gravitational potential energy of 7000 MJ with respect to Earth’s surface and a kinetic energy of 4000 MJ. At another point in its orbit, the satellite’s potential energy is 2000 MJ. What is its kinetic energy at that point? Show all calculations leading to your answer.

If a stationary cart is struck head-on by a cart with twice mass of the stationary one and a velocity of 5 m/s, what will be the new velocity of the stationary cart if the collision is inelastic? Show all calculations leading to an answer.

A 2.0-gram bullet is shot into a tree stump. It enters at a speed of 3.00 x 104cm/s and comes to rest after having penetrated 0.05 m in to the stump. What was the average force during the impact? Show all calculations leading to an answer.

**Final**

Consider eight,eight-cubic centimeter (8 cm3) sugar cubes stacked so that they form a single 2 x 2 x 2 cube. How does the surface area of the single, large cube compare to the total surface area of the individual eight cubes? Report your answer as a ratio. Be sure to show all calculations leading to an answer.

A rectangular barge 7 m long and 2 m wide floats in fresh water. How much will the barge sink when loaded with 600 kg of sand? Show all calculations leading to an answer.

In a lab experiment, 45 grams of a metal are heated from 22⁰C to 78⁰C by the addition of 450 J of heat. What is the specific heat of the metal? Show all calculations leading to an answer.

A photon of light has a wavelength of about 600 nm (1nm = 1 x 10-9 m). What is the energy of this photon of light? Show all calculations leading to an answer.

An ammeter indicates the current for a toaster is 5.0 amps when the toaster is connected to 120-V circuit. How much energy is given off by the toaster in 55.0 seconds? Show all calculations leading to an answer.

The isotope, Carbon-14 emits beta radiation and has a half live of 5730 years. How long will it take for the amount of radiation this gives off to drop by a factor of 4?

The total U.S. consumption of electricity in a particular year was 5.0 x 1012 kilowatt-hours. What is the mass equivalence of this amount of energy? Show all calculations leading to an answer.

When uranium-238 emits an alpha particle, what isotope is created? Show the nuclear equation for this reaction.

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