A car travels downhill at 72 mile/hour, on level ground at 63 mile/hour, and uphill at only 56 mile/hour. The car takes 4 hours to travel from town A to town B. The return trip takes 4 hour and 40 mines. Find the distance between the two towns.

In a physics lab experiment, a compressed spring launches a 36 g metal ball at a 35 ∘ angle. Compressing the spring 20 cm causes the ball to hit the floor 2.0 m below the point at which it leaves the spring after traveling 5.9 m horizontally. Part A What is the spring constant? Express your answer to two significant figures and include the appropriate units.

Derive an expression for the magnitude of the acceleration of the system using Newton’s laws given the presence of kinetic friction

When a ball is launched from the ground at a 45° angle to the horizontal, it falls back to the ground 50 m from the launch point. If it is launched at the same speed directly upward, (a)how high does it get? (b)How much longer does it spend in the air

What's the different between force and motion in your own word

a) Monochromatic light of variable wavelength is incident normally on a thin sheet of plastic film in air. The reflected light is a maximum only for 487.9 nm and 683.0 nm in the visible spectrum. What is the minimum thickness of the film (n=1.58)?

t = _________ nm

b) A planoconvex lucite lens 3.6 cm in diameter is placed on a flat piece of glass as in the figure 34-18 in the textbook. When 600 −nm light is incident normally, 47 bright rings are observed, the last one right at the edge.

What is the radius of curvature of the lens surface?

R = ___________ m

What is the focal length of the lens?

f = ____________ m

The Rosetta space probe has a mass of 1200 kg. On November 12th 2014,Rosetta landed on Comet 67P/C-G which has a mass of M= 1×10 ^18 kg. The instant before landing was initiated, scientists found Rosetta’s relative (to the comet) position and velocity to be: r=〈3×10^3,0,5×10^3m v=〈−1×10^2,2×10^2,0〉m/s Calculate the (approximate) momentum and position of the space probe 100 seconds later. Start from a fundamental principle and show all steps in your work. Express your final answer as three-component vectors.

How Kerma and Absorbed dose can be calculated and measured?

Two strings on a musical instrument are tuned to play at 392 Hz(G) and 494 Hz (B).

Part A

What are the frequencies of the first two overtones for G?

Got this, the answer was 784 and 1180

Part B

What are the frequencies of the first two overtones for B?

Need this

Part C

If the two strings have the same length and are under the same tension, what must be the ratio of their masses mGmB?

Got this. It was 1.59

Part D

If the strings, instead, have the same mass per unit length and are under the same tension, what is the ratio of their lengths ℓG/ ℓB?

Need this

Part E

If their masses and lengths are the same, what must be the ratio of the tensions in the two strings?

Need this

I need part B, D, and E

A 2.0 kg wood block is launched up a wooden ramp that is inclined at a 28 ∘ angle. The block's initial speed is 15 m/s . The coefficient of kinetic friction of wood on wood is μk=0.200.

What vertical height does the block reach above its starting point?

What speed does it have when it slides back down to its starting point?

A proton and an alpha particle are momentarily at rest at a distance r from each other. They then begin to move apart. Find the speed of the proton by the time the distance between the proton and the alpha particle doubles.

Both particles are positively charged. The charge and the mass of the proton are, respectively, e andm. The charge and the mass of the alpha particle are, respectively, 2e and 4m.

A- Find the speed of the proton (vf)p by the time the distance between the particles doubles.

Express your answer in terms of some or all of the quantities e, m, r, and ?0.

B- The best way to check whether your result from Part A is correct is to check that it has the correct units. Which of the following expressions, where C stands for coulombs, N for newtons, kg for kilograms, and m for meters, represents the correct SI units for the expression found in part B?

Traumatic brain injury such as concussion results when the head undergoes a very large acceleration. Generally, an acceleration less than 800 m/s2 lasting for any length of time will not cause injury, whereas an acceleration greater than 1,000 m/s2 lasting for at least 1 ms will cause injury. Suppose a small child rolls off a bed that is 0.61 m above the floor. If the floor is hardwood, the child's head is brought to rest in approximately 2.3 mm. If the floor is carpeted, this stopping distance is increased to about 1.2 cm. Calculate the magnitude and duration of the deceleration in both cases, to determine the risk of injury. Assume the child remains horizontal during the fall to the floor. Note that a more complicated fall could result in a head velocity greater or less than the speed you calculate.

(a) How would you place two electrons on a sphere of radius R so that the electrostatic potential energy is minimized. How would you place three electrons to solve the same problem.

(b) Explain in physical terms how a microwave oven works. What would happen when you put a conductor in the microwave oven? Explain.

During an earthquake, a floor oscillates horizontally in approximately simple harmonic motion. Assume it oscillates at a single frequency with a period of 0.67 s.

(a) After the earthquake, you are in charge of examining the video of the floor motion and discover that a box on the floor started to slip when the amplitude reached 11 cm. From your data, determine the coefficient of static friction between the box and the floor.

______________

(b) If the coefficient of friction between the box and floor were 0.39, what would be the maximum amplitude of vibration before the box would slip?

_______________cm

An insulated beaker with negligible mass contains liquid water with a mass of 0.285 kg and a temperature of 73.2 ∘C .

How much ice at a temperature of -13.0 ∘C must be dropped into the water so that the final temperature of the system will be 39.0 ∘C ?

Take the specific heat of liquid water to be 4190 J/kg⋅K , the specific heat of ice to be 2100 J/kg⋅K, and the heat of fusion for water to be 3.34×10⁵ J/kg .