Consider a 80.0-kg man standing on a spring scale in an elevator. Starting from rest, the elevator ascends, attaining its maximum speed of 1.36 m/s in 0.700 s. It travels with this constant speed for the next 5.00 s. The elevator then undergoes a uniform acceleration in the negative y direction for 1.70 s and comes to rest.

I can't seem to get the right answer on this one. Please help. Can someone show me the steps?

Collisions in 1-D

One cart with some mass Mc travels without friction on a 1-D tack at a speed of 1.75 m/s. Another cart sits at rest some distance along the track. The two cars will collide in a perfectly elastic collision. Calculate the final speed of each cart in the following scenarios:

A) The stationary cart has a mass equal to that of the moving cart, Mc

B) The stationary cart has a mass equal to half that of the moving cart, .5xMc

C) The stationary cart has a mass equal to 10 times that of the moving cart, 10xMc

Match each statemet with one of the following options

A: ... the same

B....the same

Select the correct statements in the following list.

A horizontal wire carries a current straight toward you. From your point of view, the magnetic field caused by this current circles the wire in a  counter-clockwise direction

The voltage across the terminals of a battery when a current flows is called the electromotive force.

If you connect two identical storage batteries together in parallel, and place them in a circuit, the combination will provide twice the voltage.

A charged particle moves across a constant magnetic field. The magnetic force on this particle causes the particle to accelerate.

A nuclear power reactor produces 3GW of thermal power from the fission of 235U for a period of 10 weeks and then it is shut down. Note: All numerical answers are expected with 3 significant figures. (a) Assuming 78% of the 200MeV released per fission event is converted to heat, estimate the number of 235U nuclei fissioned over the 10 week period. (b) 6 % of the 235U fission events produce as a fission fragment some radioactive nuclide X (e.g. 137Cs), which has a half-life of 38 years. Consider the amount of X nuclei produced during the 10 week operation of the reactor in Part A and calculate the activity of X left in the used fuel 38 years after the reactor is stopped. (c) Following Part B, estimate the power (in kW) produced by these decays of X 38 years after the reactor shutdown if each decay of X releases 1.6 MeV .

Do this problem by making a neat, precise scaled drawing, using a ruler and protractor, ready to be turned in at the start of our next class. NOTE: "azimuth" means compass direction. North is considered 0°, east is 90°, south is 180°, and west is 270°.

Dr. Evil has been captured and is in a prison awaiting trial. His minions fly a helicopter to the prison, land in the courtyard, and hurriedly get him aboard. They take off. Hoping to confuse the police, they fly 35 km at azimuth 72°, then turn and go 57 km toward azimuth 52°, then turn again and fly 30 km at azimuth 325°, arriving at Dr. Evil's secret lair.

1. How far east of the prison is Dr. Evil's lair? (Negative if the final position is west.)

2. How far north of the prison is Dr. Evil's lair? (Negative if the final position is south.)

The prison authorities track the flight on radar, and thereby learn the location of Dr. Evil's secret lair. They have another helicopter, and take off to recapture Dr. Evil. They fly straight there from the prison.

3. How far do they have to fly distance:

4. and in what direction? azimuth: °

David is driving his prius on the freeway and reaches his exit. The exit has a radius of curvature of 25 m and is banked at 38 degrees. How fast can David travel around the curve on a dry day (where the coefficient of friction between his tires and the road is 1)? How fast can he travel around the curve on a rainy day (when the coefficient of friction between his tires and a wet road is 0.75)? Give your in miles per hour. Show all work and explain each step.

Firemen are shooting a stream of water at a burning building. A high-pressure hose shoots out the water with a speed of 27.0m/s as it leaves the hose nozzle. Once it leaves the hose, the water moves in projectile motion. The firemen adjust the angle of elevation of the hose until the water takes 3.30s to reach a building 45.0m away. You can ignore air resistance; assume that the end of the hose is at ground level.

A) Find the angle of elevation of the hose.

B) Find the speed of the water at the highest point in its trajectory. (m/s)

C) Find the acceleration of the water at the highest point in its trajectory. (m/s^2)

D) How high above the ground does the water strike the building? (m)

E) How fast is it moving just before it hits the building? (m/s)

When you calculate the net electric field in a location due to the presence of more than one large charge (Q), it is generally not helpful to include the sign of the charges in the
equation for electric field. Why not? Specifically, what does the sign of a charge tell you about the direction of the electric field, and what does the sign of a charge NOT tell you
about the direction of the electric field?

1.) What is the Hall effect, give a real life example, list its applications.

2.) When an electric light bulb is operated on a low frequency AC, they noticeably flicker (for example 5Hz) why?

1. Use basic laws of physics to explain the following situations:

a. Spiderweb has a greater tensile strength than steel, yet you can snap a spider web very easily with your hand. Explain why this is so.

b. Use Bernoulli's Principle to explain how the shape of an airplane wing creates a "lift force."

c. Why is it easier to sew with a sharp needle than it is to sew with a dull one?

d. Describe how the speedometer of your car is able to tell how fast the car is going.

One billiard ball is shot east at 1.9m/s . A second, identical billiard ball is shot west at 0.90m/s . The balls have a glancing collision, not a head-on collision, deflecting the second ball by 90? and sending it north at 1.31m/s .

1.)What is the speed of the first ball after the collision?

2.)What is the direction of the first ball after the collision? Give the direction as an angle south of east.

is astronomy based on probability and chance? Are certain laws well defined, and verified through experimentation?

20 km east plus 10 km northeast

Moon effect. Some people believe that the Moon controls their activities. If the Moon moves from being directly on the opposite side of Earth from you to being directly overhead, by what percentage does (a) the Moon's gravitational pull on you increase and (b) your weight (as measured on a scale) decrease? Assume that the Earth–Moon (center-to-center) distance is 3.82 × 108 m, Earth's radius is 6.37 × 106 m, Moon's mass is 7.36 × 1022 kg, and Earth's mass is 5.98 × 1024 kg.