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3 years ago

The law of equal areas suggests that planets move fastest when at and slowest when at .

1 answer:

5 0

The law of equal areas suggests that planets move fastest when at "perihelion" at slowest when at the "aphelion." Perihelion refers to the point at a planet's orbit, comet or asteroid where it is closest to the sun. Aphelion <span>refers to the point at a planet's orbit, comet or asteroid where it is furthest to the sun.</span>

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You and your fellow students have been challenged to design a rubber band powered car. You will use the elastic potential energy

Tcecarenko [31]

Answer:

The correct answer is A

Explanation:

3 0

3 years ago

A 55 kg track and field athlete has an average power output of 5.4 kW during the 200 meter dash. How quickly did she finish the

olga_2 [115]

The time taken for the athlete to finish the race is 20 s (Option A)

<h3>What is power? </h3>

Power is simply defined as the rate at which work is done. It can be expressed mathematically as

Power (P) = work (W) / time (t)

But

Work = weight × distance

Therefore,

Power = (weight × distance ) / time

<h3>How to determine the time </h3>

Mass (m) = 55 Kg
Acceleration due to gravity (g) = 9.8 m/s²
Weight = mg = 55 × 9.8 = 539 N
Power (P) = 5.4 KW = 5.4 × 1000 = 5400 W
Distance (d) = 200 m
Time (t) =?

Power = (weight × distance ) / time

5400 = (539 × 200) / t

5400 = 107800 / t

Cross multiply

5400 × t = 107800

Divide both side by 5400

t = 107800 / 5400

t = 20 s

Learn more about power:

brainly.com/question/5684937

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5 0

2 years ago

If a cart goes around a turn at 20 km/h ,what remains constant

Vitek1552 [10]

Answer: 4.speed

Explanation:

In this case, we know that the cart remains at a constant 20km/h.

Now, one could say that "the velocity remains constant, because it always is 20km/h"

But remember that velocity is a vector, so this has a direction, and if the cart is going around a turn, then the direction of motion is changing, which tell us that there is acceleration.

But the module of the velocity, the speed, remains constant at 20km/h.

Then the correct option is 4, speed.

7 0

3 years ago

A 40 kg boy is moving upwards upwards in a lift with an acceleration of 2 m /s ^2 what would be the weight felt by him if measuu

neonofarm [45]

Answer:

$f = ma \\$

$w \: = \frac{f}{g} \\$

Explanation:

$f \: = ma \\ f - mg = ma \\ f = ma + mg \\ f = 40 \times 2 + 40 \times 10 \\ f = 480$

$w = \frac{f}{g} \\w = \frac{480}{10} \\ w = 48kg$

5 0

3 years ago

1.3 kg of water, at an initial temperature of 25oC, is heated at a rate of 100 W in a well-insulated container. How much time (i

Leviafan [203]

Answer:

68.25 minutes.

Explanation:

Power = Energy/time or

Power = Heat/time

P = Q/t....................... Equation 1

Q = Pt ........................ Equation 2

Where Q = quantity of heat, P = power, t = time.

Also,

Q = cm(t₂-t₁) ................. Equation 3

Where c = specific heat capacity of water, m = mass of water, t₁ = initial temperature of water, t₂ = final temperature of water.

substitute equation 2 into equation 3

Pt = cm(t₂-t₁) ............... Equation 4

make t the subject of the equation

t = cm(t₂-t₁)/P................ Equation 5

Given: P = 100 W, m = 1.3 kg, t₁ = 25 °C, t₂ = 100 °C.

Constant: 4200 J/kg.K

Substitute into equation 5

t = 1.3(4200)(100-25)/100

t = 409500/100

t = 4095 seconds

t = (4095/60) minutes = 68.25 minutes.

Hence the time it will take the water to reach boiling point = 68.25 minutes

6 0

3 years ago