A softball is hit over a third baseman's head with speed v0 and at an angle θ from the horizontal. Immediately after the ball is hit, the third baseman turns around and runs straight back at a constant velocity V=7.00m/s, for a time t=2.00s. He then catches the ball at the same height at which it left the bat. The third baseman was initially L=18.0m from the location where the ball was hit at home plate.  

1) Find a vector expression for the velocity v⃗  of the softball 0.100 s before the ball is caught.

Use the notation vx, vy, an ordered pair of values separated by a commas Express your answer numerically in meters per second to three significant figures.

2) Find a vector expression for the position r⃗  of the softball 0.100 s before the ball is caught.

Use the notation x, y, an ordered pair of values separated by a comma, where x and yare expressed numerically in meters, as measured from the point where the softball initially left the bat. Express your answer to three significant figures.

The coefficient of expansion for liquids is:

a) greater than that for solids

b) different for different temperatures

c) smaller as the volume changes

d) greater as the volume changes

What is the difference between phase velocity and phase angle?

What theoretical explanations exist for the fact that there are three generations of leptons and quarks?

I'm not so much asking why there are exactly 3 generations, but rather what makes electron, muon and tau differ. Also, since the three families of quarks don't have to be a priori related to the three families of leptons, I'm interested in answers for either quarks, leptons, or both.

3. A cube of Brass (B = 70 GPa) measuring 1.0 m on each side is submerged under water. It is lowerd to a depth where a force "F" is acting perpendicularly into each side, reduces the cube's volume by 1.8 %.

(a) Calculate the size of this force.

2.A researcher examines a piece of fresh human cartilage, with an area of 1.9 cm2. She observes that when subjected to a tensile force of 194 N it stretches by 4.8 %.

(a) Calculate the elastic modulus of cartilage.

1. A student pushes on the end of a helical spring, which in turn presses a 1.25 kg, wooden block onto a vertical wall. The coefficient of static friction between the block and wall is 0.5. She compresses the spring 5.2 cm.

(a) Calculate the minimum spring constant necessaary to prevent the block from sliding down the wall.

1. Explain the physical reason that this change in Planck's expression avoided the ‘Ultraviolet Catastrophe’.

2. Calculate the probability of finding the particle within the finite wall of the box when the particle is in the lowest and highest bound energy states of the box with one finite wall described above. Assume that the coefficient D is approximately D= (2/L)^1/2

Every second at a particular waterfall, some 6996 m³ of water falls a distance of 37 m. What is the increase in entropy in kJ/K, per second due to the falling water? (Assume a 23°C environment).

part a ) A person throws an object with mass m nearly vertically with an initial momentum p=(px,py,pz). With respect to the cartesian coordinate system where the person is looking in the direction y, with x directed to their right. Let ∝ be the elevation angle of the initial momentum (with respect to the x-y plane) and let θ be the angle of the initial momentum with respect to the y-z plane. Write parametric equations for the trajectory of the center of mass of the object.

part b) How high would the object need to be thrown if three objects are to be juggled at 120 beats per minute (each object is thrown in turn one at a time and one per beat) with a horizontal displacement of approximately 0.30 m? use g = 9.81.

what is the discussion and conclusions for the trajectories physics lab?

A shot putter threw a shot at an angle of 43o above the horizontal from a height of 2.0 m above the ground. The shot traveled 19.0 m horizontally from the launch position. (a) What was the initial speed of the shot when it left the shot putter’s hand? (b) How long was the shot in the air? {13.0 m/s, 2.0 s}

OSHA, the Occupational Safety and Health Administration, has established shandards for workplace exposure to noise. According to OSHA's Hearing Conservation Standard, the permissible noise exposure per day is 93.0 dB for 4 hours or 103 dB for 1 hour. Assuming the eardrum is 9.5 mm in diameter, find the energy absorbed by the eardrum, when subjected to each of these conditions.

(a) 93.0 dB for 4 hours

(b) 103 dB for 1 hour

(c) Is OSHA's safety standard simply a measure of the amount of energy absorbed by the eardrum?
Y or N
Explain.

The position of a particle is given by x = 1/3t3 - 2t2 and y = 1/2t2 - 2t. Positions are in meters and time is in seconds. Complete the following table. θ is the angle between v and a, dv/dt is the rate at which the speed is changing, and R is the radius of the trajectory's tangent circle.

1)During a thunderstorm, a lightning "bolt" carries current between a cloud and the ground below. If a particular bolt carries a total charge of 39 C in 1.2 ms, what is the magnitude of the current?
A

How many electrons are involved in this process?
electrons

A cart of mass m1 = 11 kg slides down a frictionless ramp and is made to collide with a second cart of mass m2 = 24 kg which then heads into a vertical loop of radius 0.25 m (a) Determine the height h at which cart #1 would need to start from to make sure that cart #2 completes the loop without leaving the track. Assume an elastic collision. (b) Find the height needed if instead the more massive cart is allowed to slide down the ramp into the smaller cart.