A soccer player kicks the ball toward a goal that is 27.6 m in front of him. The ball leaves his foot at a speed of 18.5 m/s and an angle of 31.2° above the ground. Find the speed of the ball when the goalie catches it in front of the net. (Note: The answer is not 18.5 m/s.)

I keep getting a final velocity of 13.92797m/s but its incorrect. Please show your work so I can see what I'm doing wrong.

Internal injuries in vehicular accidents may be due to what is called the "third collision" The first collision is the vehicle hitting the external object. The second collision is the person hitting something on the inside of the car, such as the dashboard or windshield. This may cause external lacerations. The third collision, possibly the most damaging to the body, is when organs, such as the heart or brain, hit the ribcage, skull, or other confines of the body, bruising the tissues on the leading edge and tearing the organ from its supporting structures on the trailing edge.

A) Why is there a third collision? In other words, why are the organs still moving after the second collision?

B) If the vehicle was traveling at 60 mph before the first collision, would the organs be traveling more than, equal to, or less than 60 mph just before the third collision?

Explain your answers in essay form:

A 120 V rms voltage at 60.0 Hz is applied across an inductor, a capacitor, and a resistor in series. If the peak current in this circuit is 0.84840 A, what is the impedance of this circuit?

• For two objects dropped at two different times from the same location (e.g. a bridge), while both are still

  in free-fall describe how their velocities and their distances change through time (neglecting air

  resistance).

• An example would be appreciated

A 0.50-kg mass vibrates according to the equation x = 0.35 sin (5.50 t) where x is in meters and t is in seconds. Determine (A) the amplitude, (B) the frequency, (C) the total energy, and (D) the kinetic energy and potential energy when x = 0.3m Please Explain.

(1) A block is placed on a wooden plank, which is initially horizontal. One end of the plank is slowly raised to make it more and more inclined, and for a while the block stays in place on the plank and doesn't slide due to static friction. Finally, when the plank reaches an incline of 56.3^o above horizontal, the block begins to slide. What is the  coefficient of static friction between the block and the plank?

(2) Continuing the story... after the block begins sliding down the incline at 56.3^o, you measure its acceleration down the plank as 7.42 m/s². What is the coefficient of kinetic friction between the block and the plank?

These will be clicker questions on Wednesday, and we will work together through some problems involving tension and pairs of objects.

Suppose a 10 kg ball makes a one dimensional collision with a 5 kg ball. Think about what could happen to the velocity of the 5 kg ball as a result of the collision. Could it remain unchanged? Could it increase? Could it decrease? Is it possible for both balls to end up traveling in the same direction after the collision? For each result you think could happen, please briefly explain why and offer an example of starting conditions that would cause that result. If you think a certain result couldn't happen, please also briefly explain why.

A  green laser operates at 488.0 nm with an output power of 2.5 mW. Calculate the average output in photons/s (“photon flux”). What would the output power be for the same flux of 244.0 nm photons? What would the photon flux be for a 488.0 nm laser operating at 5.0 mW?

A charge of -5.50nC is spread uniformly over the surface of one face of a nonconducting disk of radius 1.00cm

Part A

Find the magnitude of the electric field this disk produces at a point P on the axis of the disk a distance of 3.00cm from its center.

Part B

Suppose that the charge were all pushed away from the center and distributed uniformly on the outer rim of the disk. Find the magnitude of the electric field at point P.

Part C

If the charge is all brought to the center of the disk, find the magnitude and direction of the electric field at point P.

Part D

Why is the field in part (a) stronger than the field in part (b)?

Part E

Why is the field in part (c) the strongest of the three fields?

A 4 kg block is placed at the top of an inclined plane. The plane is 2.5 meters long and inclined at 34°. The coefficient of kinetic friction between the block and plane is 0.27. The block slides the 2.0 meters down the ramp. What speed does it have at the bottom?

What is the relationship between the index of refraction and the density of the transparent material? Is this relationship a rule of thumb or is it an absolute?

Water flows through the pipe in the figure below and exits to the atmosphere at the right end of section C. The diameter of the pipe is 2.12 cm at A, 4.24 cm at B, and 0.880 cm at C. The gauge pressure in the pipe at the center of section A is 1.25 atm and the flow rate is 0.856 L/s. The vertical pipes are open to the air. Find the level (above the flow midline as shown) of the liquid-air interfaces in the two vertical pipes. Assume laminar nonviscous flow.
h_A = m

h_B = m