A 250 N force pulls on a box horizontally to the right. The box is moving at constant speed.

A ski lift has a one-way length of 1 km and a vertical rise of200m. The chairs are spaced 20 m apart, and each chair can seatthr

Strike441 [17]

Answer:

a) 68.125 KW

b) 43.04 KW

Explanation:

Distance =d= 1 km

Height = h = 200 m

Spacing between chairs =D= 20 m

No. of people per chair = 3

Speed = V= 10 km/h= 10000m\3600 s=2.8 m/s

mass of chair = 250 kg

Work to operate sky lift

W= mgh

Number of chairs any moment operational = N= 1 km/20=1000m/20=50

So, total mass of chairs = 50 × 250 =12500kg

so, w= mgh=12500×9.8×200=2452500 j

Power is rate of work - we need time for operation time of lift

Time= t = distance/speedf= 1km/(10km/h)=1km/(10 km/3600s)=360s

So, Power P= Work/time=w/t=12500/360=68125 j/s=68.125 KW

Now calculating power for operating speed in 5 sec

We calculate accelleration=a for 5 sec

a= speed / time= V/52.8/5=0.28 m/sec2

for vertical acceleration we calculate θ angle first;

tanθ= height /distance= 200/1000= 0.2

==> θ=11.34°

Vertical acceleration = a₁=a sinθ= 0.28× sin 11.34=0.10835 m/sec2

to calculate height gained during startup use;

S=vit+1/2at2

here s=H

vi=0m/s

t=5 sec

==> H = 0+1/2a₁×t=0.5×0.10835 ×5²=0.5×0.10835×5×5=1.362 m

Total Work =mgH+0.5×m×V²=12500(9.8×1.362+0.5×2.8×2.8)=215240.56 j

Again power = work / time=215240.56/5=43048.112 W=43.04 KW

6 0

3 years ago

A racquetball with a mass of 42 g is moving with a horizontal speed of 7 m/s to the right (+x direction). It hits the wall of th

zheka24 [161]

The magnitude of the racquetball's change in momentum is 0.59 kgm/s approximately.

Given that a racquetball with a mass of 42 g is moving with a horizontal speed of 7 m/s to the right (+x direction).

mass m = 42g = 42/1000 = 0.042kg

initial velocity before collision u = 7 m/s

It hits the wall of the court and rebounds to the hitter with a horizontal speed of 7m/s to the left (-x direction). That is,

velocity after collision v = 7 m/s

To calculate the magnitude of the racquetball's change in momentum, we will use the formula below

Change in momentum = Mv - Mu

Since momentum is a vector quantity, we will consider the direction.

Change in momentum = 0.042 x 7 - ( 0.042 x - 7)

Change in momentum = 0.294 + 0.294

Change in momentum = 0.588 kgm/s

Therefore, the magnitude of the racquetball's change in momentum is 0.59 kgm/s approximately.

Learn more on momentum here: brainly.com/question/402617

5 0

3 years ago

PLZ HELP!!!!!!!

kifflom [539]

Match the basic components of a nuclear reactor with their descriptions. 1. slows down neutrons moderator - This is the substance that slows down fast neutrons and makes them slow neutrons which are easier to capture by the atomic nuclei so that the fission reaction can continue. 2. absorb emitted neutrons control rods - These are rods made up of a substance that easily absorbs neutrons. Their purpose is to slow down or shut down the reaction. 3. mass of unstable atoms nuclear fuel - The entire point of a nuclear reactor is the capture the energy released by the fission of unstable atoms. So this mass of unstable atoms is the fuel for the nuclear reactor. 4. concrete and lead enclosure shield - This is the enclosure that prevents radiation from escaping into the general environment. 5. energy transfer medium coolant - Since the purpose of a nuclear reactor is to generate usable energy, the coolant extracts heat from the fissioning core and that heat is generally used to boil water which in turn is used to operate turbines that power electrical generators.

3 0

3 years ago

Read 2 more answers

To dry the brakes, drive slowly in __________ and apply light pressure on your brake pedal.

ira [324]

The answer is low gear. To dry the brakes of a vehicle, one must driv slowly in low gear and apply light pressure on the vehicle's brake pedal. Dry brakes are less expensive and are cheap when it needs replacement, yet under pressure they may cause more damage to the system than wet brakes, which are better in terms of emergency.

3 0

3 years ago

Hey solution that contains all of the salute it can normally hold at a given temperature is

ankoles [38]

Answer:

A saturated solution

Explanation:

A saturated solution is one that contains the most amount of solute that can be dissolved in it at a given temperature

An example of a saturated solution is carbonated water, which readily gives off bubbles of carbon dioxide gas from areas within the solution to the region above the top surface of the gas in liquid solution

A saturation solution of salt in water can be created by continuing to dissolve salt in a given amount of water until it can no longer dissolve any more salt. However, heating the saturated salt solution, increases the amount of salt that can be dissolved.

Therefore, a solution that contains all of the solute it can normally hold at a given temperature is a saturated solution

8 0

3 years ago