Now let's consider the impulse associated with kicking a soccer ball (Figure 1). The ball has mass 0.40 kg . Initially it moves horizontally to the left at 20 m/s, but then it is kicked and given a velocity with magnitude 30 m/s and direction φ=45∘ upward and to the right. Find the impulse of the force and the average force on the ball, assuming a collision time Δt=0.010s.

angle: 27

Part A:Suppose the ball is moving at 30 ∘ downward from the horizontal before it is kicked. If all the numerical values are the same as before, find the magnitude of the average force on the ball. Express your answer in newtons to two significant figures.

Part B:Find the direction of the average force on the ball found in Part A. Express your answer in degrees to two significant figures.

Suppose that an event occurs in the reference frame S with coordinates x = 2m, y = 0m and z = 0m at t = 4m/c. The frame S’ moves in the positive x-direction with velocity u = 0.2c. The origins of S and S’ coincide at t = t’ = 0. a. Use the Lorentz transformations to find the coordinates of the event in S’. b. Use the inverse transformation on the results of (a) to obtain the original coordinates and time.

The trajectory of a rock thrown from a height with an initial speed of 19.7 m/s is shown in the figure below. Evaluate the magnitude of the gravitational field at the surface of the planet. The planet has no atmosphere.

How do you determine what velocity and angle is needed so that both the x and y displacement are equal to each other at a specific point?

For example if a projectile is launched on a 100m cliff, what velocity and angle is needed so that both the x and y displacement points are equal to 160m?

Which of the following inertial reference frames are proper frames for the two events listed? Choose all that apply.

RED FRAME: Event A happened at a different place than event B.

ORANGE FRAME: Event C happened at (-7 m, 3 m, 4 m) and event D happened at (-7 m, 3 m, 5 m).

YELLOW FRAME: The distance between where event E occurred and where event F occurred was 0 m.

GREEN FRAME: A rocket was traveling at a constant velocity when it passed through a stationary tunnel. Event G was the front of the rocket entering the tunnel and event H was the the front of the rocket leaving the tunnel.

BLUE FRAME: A stationary rocket was engulfed by a hollow cylinder that was moving at a constant velocity. Event J was the front of the rocket entering the cylinder and event K was the the front of the rocket leaving the cylinder.

A pitcher rotates his arm to throw a baseball. The distance from the centre of rotation of the pitcher's arm to his hand is 110 cm and remains constant over the throw. At the start of the throw, the pitcher's arm is already rotating at 0.250 rad/s and it takes him 250 ms to complete the throw. if the arc length that his hand traces over the throw is 2.70m, calculate the transverse velocity of his hand at the end of the throw.

Which one would have the biggest impact? Why?

A 200-g ball is dropped from rest from a height of 1.4 m. It bounces and returns to the same position.  

a) What is the change in momentum between the two points?

b) If the ball is in contact with the floor for 10-³ s, what impulse does the floor impart to the ball?  

In these cases remember vectors.

Write out the matrix based on the secular equations for benzene using the huckel approximation.

1. At what speed does a 1700 kg compact car have the same kinetic energy as a 1.80×10⁴ kg truck going 23.0 km/hr ?

2.The cable of a crane is lifting a 850 kg girder. The girder increases its speed from 0.25 m/s to 1.25 m/s in a distance of 3.5 m.

Part 1: How much work is done by gravity? Express your answer with the appropriate units.

Part 2: How much work is done by tension? Express your answer with the appropriate units.

How the concentration polarization occurs in galvanic and electrolylic cells (in details)

mechanism of each cell

Two charges are placed along the x axis such that charge A is at -3 m, and has a charge of 2.5e-06 C. Charge B is at 2.2 m, and has a charge of -2.5e-06 C.
What is the x component of the force (in Newtons) felt by charge A due to charge B?
What is the x component of the force (in Newtons) felt by charge B due to charge A?
Suppose a third charge were to be placed at position C, -5.6 m on the x axis. What is the x component of the electric field at position C?

How much horsepower would a car need to tow a boat up the Davis Dam Grade Climb?

Pro Tips

Davis Dam assumed grade = 7%

Air density is sea level conditions (.002377 slugs/f^t3)

w(weight) of the boat + trailer + car = 3,922,000 + 150,000 + 4451 Lbs

Crr = coefficient of rolling resistance = .015

Assume Combined CDA is 1555 ft^2

SAE J2807 (Davis Dam Grande Climb) - min speed is 40mpg (59 ft/s)

F(drag) = 1/2p x V^2 x C(d)A

F(rolling resistance) = W x cos x Crr

F(weight) = W x sin

F(sum) = F(drag) + F(rr) + F(weight)

P = F(sum)XV

convert to horsepower = P(1hp/550ft lbf/sec)

Concentrated solar power is a method of using the Sun's light to produce useful energy on Earth. A large system of mirrors collects light during the day and focuses it on a target which is raised to a high temperature. The energy delivered to the target is then used to generate steam which runs turbines to produce electricity. The mirrors do not have to be circular, and for some designs they focus light along a line rather than to a point .

Concentrated solar power is a practical alternative to direct solar "photovoltaic" electric because the efficiency is high and because the energy collected may be stored, for example in molten salts. However, it has a very significant environmental impact on wildlife because intense converging light may endanger birds and bats. A way to reduce that risk is to lower the temperature by collecting light in long cylindrical troughs.

1. Suppose you wanted to collect power sufficient for 10,000 homes, which on average use about 10,000 kilowatt hours a year each. Given a solar constant of 1.4 kW/m², at a site with 300 clear days a year, how much area would be needed to gather the power required? Assume the turbines have an efficiency of 40% and there are 8 hours a day of useful sunlight. Given that area, if it is covered by mirrors in a square array, what is the size of the square along one side in meters? Explain.

2. To save birds and avoid singed technicians, you design the array to use cylindrically shaped mirrors focusing light to a line on long pipes. In this way the delivered power is distributed over a larger target and the temperature of the target is kept low. What is the ideal shape of the mirror? If approximately that shape were a cylinder with a diameter of 4 meters, where would the pipe have to be above the mirror's surface?  

3. The source of the energy collected by this power station is the fusion of hydrogen within the Sun's core where it is converted to helium with a small loss of mass. How much mass does the Sun lose each year to deliver this energy to a solar power system on Earth?

The average net torque Justin exerts on a discus about its axis of spin is 100 Nm during a throw. The mass of the discus is 2 kg, and its radius of gyration about the spin axis is 12 cm. If the discus is not spinning at the start of Justins throwing action, and the throwing action lasts for 0.20 s, how fast is the discus spinning when Justin releases it?