A 1.85 kg block slides with a speed of 0.955 m/s on a frictionless horizontal surface until it encounters a spring with a force constant of 980 N/m . The block comes to rest after compressing the spring 4.15 cm.

A.Find the spring potential energy, U, the kinetic energy of the block, K, and the total mechanical energy of the system, E, for compressions of 0 cm.

B.Find the spring potential energy, U, the kinetic energy of the block, K, and the total mechanical energy of the system, E, for compressions of 1.00 cm.

C.Find the spring potential energy, U, the kinetic energy of the block, K, and the total mechanical energy of the system, E, for compressions of 2.00 cm.

D.Find the spring potential energy, U, the kinetic energy of the block, K, and the total mechanical energy of the system, E, for compressions of 3.00 cm.

E.Find the spring potential energy, U, the kinetic energy of the block, K, and the total mechanical energy of the system, E, for compressions of 4.00 cm.

A person is pulling a 40 kg block of ice across an icy surface at a 25 degree angle. If the person is pulling with a force of 42 N, what is the magnitude of the acceleration of the block of ice? you may ignore drag, but not friction. Us=.1 and Uk=.03

I got this wrong on the homework and my teacher said that the normal forces does not equal mg here and that the tension is "pulling up"

A merry-go-round with a moment of inertia of 750 kgm^2 and a radius of 2.55 m is rotating with an angular velocity of 9.42 rad/s clockwise (as viewed from above.) A child, whose weight is 334 N, runs at 2.76 m/s tangent to the rim of the merry-go-round and jumps onto it in the direction opposite of its sense of rotation. With what angular speed does the merry-go-round rotate after the child jumps onto its edge?

I'm pretty sure the answer is going to be negative.

Explain, in thermodynamic terms what happens and how it is achieved to ensure that an engine can operate at high altitude for commercial aircraft since the highier they go the less air is present for the engines to work with. What changes, differences in design for engines, are required for aircraft that operate at higher altitudes?

A woman of mass m = 53.4 kg sits on the left end of a seesaw—a plank of length L = 4.25 m—pivoted in the middle as shown in the figure.

(a) First compute the torques on the seesaw about an axis that passes through the pivot point. Where should a man of mass M = 67.7 kg sit if the system (seesaw plus man and woman) is to be balanced?

(b) Find the normal force exerted by the pivot if the plank has a mass of m_pl = 12.8 kg.

(c) Repeat part (a), but this time compute the torques about an axis through the left end of the plank (m).

EXERCISE

Suppose a 32.0 kg child sits 1.87 m to the left of center on the same seesaw as the problem you just solved. A second child sits at the end on the opposite side, and the system is balanced.

(a) Find the mass of the second child (kg).
m_{child 2} =

(b) Find the normal force acting at the pivot point (N).
F_n =   

On average, both arms and hands together account for 13% of a person's mass, while the head is 7.0% and the trunk and legs account for 80%. We can model a spinning skater with her arms outstretched as a vertical cylinder (head, trunk, and legs) with two solid uniform rods (arms and hands) extended horizontally.

Suppose a 62.0 kg skater is 1.60 m tall, has arms that are each 64.0 cm long (including the hands), and a trunk that can be modeled as being 32.0 cm in diameter. If the skater is initially spinning at 80.0 rpm with her arms outstretched, what will her angular velocity ω2 be (in rpm) after she pulls in her arms and they are at her sides parallel to her trunk? Assume that friction between the skater and the ice is negligible.

My answer was 293.93. Please show your work so I may trackback where I went wrong thank you

A solid, homogeneous sphere with a mass of m₀, a radius of r₀ and a density of ρ₀ is placed in a container of water. Initially the sphere floats and the water level is marked on the side of the container. What happens to the water level, when the original sphere is replaced with a new sphere which has different physical parameters? (Answer choices per question: rises, falls, stays the same, rises or stays the same, falls or stays the same)
1. The new sphere has a mass of m < m₀ and a radius of r = r₀.

2. The new sphere has a density of ρ > ρ₀ and a radius of r = r₀.

3. The new sphere has a mass of m = m₀ and a density of ρ > ρ₀.

**Please explain how you got the answers also :) Thank you!

An air bubble at the bottom of a lake 32.0m deep has a volume of 1.00 cm3.

If the temperature at the bottom is 2.2 ?C and at the top 20.2 ?C, what is the radius of the bubble just before it reaches the surface?

The lab experiment is repeated with the same two glass plates but with a different human hair. The sodium vapor lamp is replaced by a monochromatic light source that produces light of wavelength

The separation between adjacent dark fringes is measured to be 0.485 mm. Calculate the diameter of the hair. (The length of the plates is 12.0 cm.)

(A.) A "healthy" systolic (during heart contraction, the high number in 120/80) blood pressure is typically 120 mmHg. What is this in Pascals? (Take the density of mercury to be 14 g/ml and the acceleration due to gravity to be 10 m/s^2) _____ Pa

I tried converting mmHg to atm (760mmHg = 1atm) and then converting atm to Pa (1 atm = 101325 Pa) and got 15998.6842 Pa, but this answer was incorrect.

(B.) Blood flows through the aorta, and the rest of the body, at a rate of 5 liters per minute.

If the aorta has a diameter of 2 cm, what is the speed of the blood flowing through it? _____ m/s

(C.) Given that the blood flow through the body is 5 liters per minute, estimate the number of capillaries there are in the body using the following. Assume the diameter each capillary is 10 micrometers and the speed of blood through them is 0.03 cm/s

(D.) During a ventricle contraction, the average pressure pushing blood into the aorta is 100 mmHg. What is this pressure in Pascals? (use the density of mercury at 14 g/ml and the acceleration due to gravity of 10 m/s^2)

______ Pa

(E.) During a contraction, the heart pumps 75 ml of blood into the Aorta. Given the pressure above, how much work is done (in Joules) on the blood by the heart during a contraction?

(F.) Assuming a heart rate of 60 beats per minute, how many Calories (kilocalories) are burned just circulating blood during a day. (Take the approximation of 4 Joules per calorie.)

. Block A and Block B start from rest on a horizontal track. An ideal string pulls cart A with a constant force of 25 N, causing both of the carts to move together as they accelerate. The coefficient of kinetic friction between the blocks and the track is 0.10. Block A= 4.0kg and Block B= 1.0kg (pulled horizontally) Determine the magnitude of each individual force that acts on Block A and each individual force that acts on Block B.

1.) Give the three mathematical definitions of conservative forces?

2.) Explain what the expression "Inertial force" means? and why are inertial forces not really forces?

3.) For pulley-type simple machines specifically, the ideal mechanical advantage is equal to ____?

4.) for ramp-type simple machines specifically, the ideal mechanical advantage is equal to ____?

The great pyramid of Giza consits of approximately 2 million stones, each weighing 1.5 tons ( 3000 lbs). The pyramid is 450 ft high and has a square base measuring 750 ft. Find the work rquired to lift the stones into place from ground level.

Would I use the integral of w=f*d; w=3000*x from 0 to 450? Do I need to do something with the square base and its volume?

Answer is 675,000,000,000 ft-lb

Thermal Storage Solar heating of a house is much more efficient if there is a way to store the thermal energy collected during the day to warm the house at night. Suppose one solar-heated home utilizes a concrete slab of area 13 m2 and 29 cm thick.

If the density of concrete is 2400 kg/m3, what is the mass of the slab?

The slab is exposed to sunlight and absorbs energy at a rate of 1.4 ×107J/h for 10 h. If it begins the day at 25 ∘C and has a specific heat of 750 J/(kg⋅K), what is its temperature at sunset?

Model the concrete slab as being surrounded on both sides (contact area 26 m2) with a 1.7-m-thick layer of air in contact with a surface that is 5.0 ∘C cooler than the concrete. At sunset, what is the rate at which the concrete loses thermal energy by conduction through the air layer?

Model the concrete slab as having a surface area of 24 m2 and surrounded by an environment 5.0 ∘C cooler than the concrete. If its emissivity is 0.93, what is the rate at which the concrete loses thermal energy by radiation at sunset?

A uniform steel rod has mass 0.300 kg and length 40.0 cmand is horizontal. A uniform sphere with radius 8.00 cm and mass 0.700 kg is welded to one end of the bar, and a uniform sphere with radius 6.00 cm and mass 0.580 kg is welded to the other end of the bar. The centers of the rod and of each sphere all lie along a horizontal line.

Part A

How far is the center of gravity of the combined object from the center of the rod?

Express your answer with the appropriate units. Enter negative value if the center of gravity is toward the 0.700 kg sphere and positive value if the center of gravity is toward the 0.580 kg sphere.