Answer: 9130 joules
Explanation:
Workdone by wheelbarrow = ?
Time = 11 seconds
Power = 830 watts
Recall that power is the rate of doing work. Thus, power is workdone divided by time taken.
i.e Power = (workdone/time)
830 watts = Workdone / 11 seconds
Workdone = 830 watts x 11 seconds
Workdone = 9130 joules
Thus, 9130 joules of work is required to get the wheelbarrow across the yard.
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
The Newton’s law Nikolas would use to come up with this idea is the <span>Third law that states:
</span><span>When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.
</span>
So, in this case, let's name the first Body
A which is the skateboard and the second body
B which is <span>the compressed carbon dioxide in a fire extinguisher. Then, as shown in the figure below, according to the Third law:
</span>

<span>
</span>
Answer: (d) It is !3 times the original speed.
Explanation: The rms speed of a gas is related to its temperature by the formulae below;
U(r.m.s) =√(3RT)/M
Where;
T represents the temperature.
R represents the gas constant.
M represents the molar mass of the gas.
Therefore, if the temperature increases from 200k to 600k
The temperature has then increased by a factor of 3,
However, we must note that temperature in the formulae is included in the square-root
Recall,
U(r.m.s) =√(3RT)/M
Consequently, temperature (T) can now be represented by (3T).
The inference drawn from this is that the root-mean-square speed would increase by a factor of √3
Therefore, option (d) is correct.
Answer:
v = 172 km/h
Explanation:
For the first 12 hours, it traveled at an average speed of 185 km/h. Let d₁ is distance. So,

For the next 13 hours, it traveled at an average speed of 160 km/h. Let d₂ is the distance. So,

Average speed = total distance/time taken
So,

So, the average speed of the whole journey is 172 km/h.