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3 years ago

Question 2 of 10

Physics

1 answer:

GaryK [48]3 years ago

6 0

Answer:

Explanation:

because it is system removed from system and it dosent interact with them

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A car with a mass of 1.50x10^3 kg starts from rest and accelerates to a speed of 18.0m/s in 12.0 s. assume that the force of res

Luden [163]

The first thing you should know for this case is the definition of distance.
d = v * t
Where,
v = speed
t = time
We have then:
d = v * t
d = 9 * 12 = 108 m
The kinetic energy is:
K = ½mv²
Where,
m: mass
v: speed
K = ½ * 1500 * (18) ² = 2.43 * 10 ^ 5 J
The work due to friction is
w = F * d
Where,
F = Force
d = distance:
w = 400 * 108 = 4.32 * 10 ^ 4
The power will be:
P = (K + work) / t
Where,
t: time
P = 2.86 * 10 ^ 5/12 = 23.9 kW
answer:
the average power developed by the engine is 23.9 kW

8 0

3 years ago

What is the average force (average with respect to height of the barbell from the ground) exerted by the weightlifter in the pro

Novay_Z [31]

This question is incomplete, the complete question is;

A weightlifter holds a 1,300 N barbell 1 meter above the ground. One end of a 2-meter-long chain hangs from the center of the barbell. The chain has a total weight of 400 N. How much work (in J) is required to lift the barbell to a height of 2 m?

What is the average force (average with respect to height of the barbell from the ground) exerted by the weightlifter in the process?

Answer: Average force exerted by the weightlifter in the process = 1600N

Explanation:

To find Work done to lift a barbell and half of the hanging chain we say;

W₁ = ( 1300N + (1/2 × 400N)) × 1m

W₁ = (1300 + 200) Nm

W₁ = 1500J

now work done to lift the upper half of the chain we say:

W₂ = (1/2 × 400N) × (1/2 × 1m)

W₂ = 200N × 0.5m

W₂ = 100J

So total work done will be

W = W₁ + W₂

W = 1500J + 100J

W = 1600J

To find the average force exerted by the weight lifter, we say;

F = W/D

F = (1600 / 1m) N

F = 1600N

∴Average force = 1600N

6 0

3 years ago

If the kinetic energy of a 32kg box is 1500 J just before it hits the ground, from what height was it dropped?If the kinetic ene

statuscvo [17]

Answer:

4.8 m

Explanation:

When it hits the ground, all the kinetic energy is converted to potential energy. Potential energy, PE is given by mgh where m is the mass of the box, g is acceleration due to gravity and h is the height which is unknown for this case

PE=mgh and making h the subject of the formula then $h=\frac {PE}{mg}$ and substituting g with 9.81, PE with 1500 J and m with 32 kg then

$h=\frac {1500}{32\times 9.81}=4.7782874617734m\approx 4.8 m$

6 0

4 years ago

Which equation represents the total energy of a system?

aev [14]

C) Total Energy = Potential Energy + Kinetic Energy

Explanation:

The total energy of a system (also called mechanical energy) is given by:

$E=PE+KE$

where

PE is the potential energy

KE is the kinetic energy

The two types of energy have a different origin:

Potential energy (PE) is the energy possessed by an object due to its position. It is commonly in the form of gravitational potential energy, which is the energy due to the position of the object in the gravitational field, defined as:

$PE=mgh$