Answer: The work done is W = 3528J.
Explanation: Work (W) is an amount of energy used to do determined movement. To calculate it, we use the formula, as the movement is horizontal:
W = F.d, where
F is force on the object
d is distance it went through.
The force acting on the crate is due to friction.
= μ .
μ is the kinetic friction
is the normal force
There is no up and down movement, so , with g = 9.8m/s²
= μ . m . g
= 0.9 . 80 . 9.8
= 705.6 N
Substituing into the work formula, we have:
W = . d
W = 705.6 . 5
W = 3528 J
The work done to move the crate across a distance of 5m is 3528 J.
Answer:
The kinetic energy is 303178 Joule
Explanation:
We must change the speed units to m / s =
1km ---- 1000meters
1h ----- 3600 seconds
v = (95km 1000m / km) / (1h x 3600s / h) = 26, 4 m / s
We use the Kinetic Energy formula: Ec = 1/2 m x v ^ 2
Ec = 1/2 x 870 kg x (26, 4) ^ 2 = 303177, 6 Joule
According to the rules for significant figures, simple decimal subtraction is done. But since 15.54 is only accurate to the hundredths place, then the resulting difference should also be rounded off to the nearest hundredths. This is shown below:
508.9538 - 15.54 = 493.4138
Rounding off to the nearest hundredths:
= 493.41
Answer:
525,000J
Explanation:
Power = work/time
Given
Power = 350 watts
Time = 25 mins = 25 x 60 = 1500 secs
Therefore
350 = work/1500
Cross multiply
Work = 350 x 1500
Work = 525,000J