A child is playing with a ball at the base of a hill. She rolls the ball up the hill with a speed of 8 m/s. After 23s, the ball comes back to her and has the same speed as when she rolled it but it's moving in the opposite direction. Assume that the ball's acceleration was constant as it rolled up and down the hill, and take the positive direction to point up the hill.

What was the ball's acceleration while rolling up and down the hill?

A swimming pool is 1.4 m deep and 12 m long. Is it possible for you to dive to the very bottom of the pool so people standing on the deck at the end of the pool do not see you?

A) Assume you dive to the very bottom of the pool so people standing on the deck at the end of the pool can see you. Find the minimum height of the person's eyes at the far side of the pool, so you would be observable by this person. Take an angle 48.5∘ for a ray that is incident at the water-air interface (nwater = 1.33).

B) Therefore, is it possible for you to dive to the very bottom of the pool so people standing on the deck at the end of the pool do not see you?

A loudspeaker of mass 17.0kg is suspended a distance of h = 2.40m below the ceiling by two cables that make equal angles with the ceiling. Each cable has a length of l = 2.50m .

What is the tension T in each of the cables?

Use 9.80m/s2 for the magnitude of the acceleration due to gravity.

A vase falls off a table and shatters into three fragments which move away horizontally across the floor. Fragment 1 has half the mass of the original vase and travels with speed 34.5 cm/s. Fragment 2 has one-quarter the mass of the original vase and travels with speed 26.6 cm/s in a direction perpendicular to Fragment 1.

What is the speed (in cm/s) of the third fragment?

Explain why there might be discrepancies for the different types of radiation if graphed in the same manner as your count rate versusinverse square of the distance graph. What type of radiation would you imagine having the most discrepancy?

Two frictionless “hoverpucks” (puck 1 and puck 2) with mass 0.20 kg are travelling on a collision course with a third hoverpuck which is at rest and has mass 0.40 kg. Before they collide, puck 1 has velocity (1.0 m/s) î – (1.0 m/s) ĵ. After the collision they all stick together and have velocity (2.0 m/s) î + (0.5 m/s) ĵ. Friction is negligible.

a) What is the velocity of puck 2 before the collision?

b) What is the total impulse on puck 1 during the collision?

c) If the duration of the collision was 0.15 s what was the average force exerted by puck 3 on puck 1?

d) How much kinetic energy is gained or lost by the three-puck system?

A block of mass m = 2.00 kg is released from rest at h = 0.400 m above the surface of a table, at the top of a ? = 40.0

Always when we want to represent the magnetic field of the earth we see a similar image:

enter image description here

My question is, what exactly does this show? What are the blue and orange lines, what do they represent? Why are they curved like that? I have a vague idea about field lines, but I do not fully comprehend this. An explanation would be appreciated

The atmosphere many times is related to the typical

1) Which is hottest? 200 F or 200 C or 200 Kelvin

2) Convert (- 40) C to Fahrenheit .

3) What is the hottest possible temperature?

4) Thermometers are used to measure temperature. There are many different types of thermometers. One type is based on a thermocouple . Briefly describe how a thermocouple works.

5) What is the recommended temperature for inside a residential refrigerator?

A bicycle wheel has a diameter of 63.7 cm and a mass of 1.83 kg. Assume that the wheel is a hoop with all of the mass concentrated on the outside radius. The bicycle is placed on a stationary stand and a resistive force of 125 N is applied tangent to the rim of the tire.

(a) What force must be applied by a chain passing over a 9.10 cm diameter sprocket if the wheel is to attain an acceleration of 4.47 rad/s2?__________N

(b) What force is required if the chain shifts to a 5.50 cm diameter sprocket?___________ N

A billiard ball of mass mA = 0.400 kg moving with a speed vA,0 = 1.80 m/s strikes a second ball, initially at rest, of mass mB = 0.500 kg. As a result of the collision, the first ball is deflected off at an angle of 30.0 o with a speed vA = 1.10 m/s.

a) What is the speed vB and angle of deflection θB of ball B? Take the x axis to be the direction of motion of ball A before the collision.

b) Is the collision elastic? You must support your answer with a calculation.

When two lenses are used in combination, the first one forms an image that then serves as the object for the second lens. The magnification of the combination is the ratio of the height of the final image to the height of the object. A 1.60cm -tall object is 51.0cm to the left of a converging lens of focal length 40.0cm . A second converging lens, this one having a focal length of 60.0cm , is located 300cm to the right of the first lens along the same optic axis.

A)

Find the location and height of the image (call it I1) formed by the lens with a focal length of 40.0cm .

Enter your answer as two numbers separated with a comma in cm

B)

I1 is now the object for the second lens. Find the location and height of the image produced by the second lens. This is the final image produced by the combination of lenses.

Enter your answer as two numbers separated with a comma in cm

If you take a two-litre plastic soda bottle and blow across the lid, you get a very low note. If you squeeze the bottle and make it flat, you get a higher note. What's going on?   

A positron with kinetic energy 2.5 keV is projected into a uniform magnetic field Bvec of magnitude 0.90 T, with its velocity vector making an angle of 89° with Bvec. Find the following values for the positron's helical path.

(a) the period

____s

(b) the pitch

____m

(c) the radius

_____m