Answer:
143.352 watt.
Explanation:
So, in the question above we are given the following parameters or data or information that is going to assist us in answering the question above efficiently. The parameters are:
"A 1.8 m wide by 1.0 m tall by 0.65m deep home freezer is insulated with 5.0cm thick Styrofoam insulation"
The inside temperature of the freezer = -20°C.
Thickness = 5.0cm = 5.0 × 10^-2 m.
Step one: Calculate the surface area of the freezer. That can be done by using the formula below:
Area = 2[ ( Length × breadth) + (breadth × height) + (length × height) ].
Area = 2[ (1.8 × 0.65) + (0.65 × 1.0) + (1.8 × 1.0)].
Area = 7.24 m^2.
Step two: Calculate the rate of heat transfer by using the formula below;
Rate of heat transfer =[ thermal conductivity × Area (T1 - T2) ]/ thickness.
Rate of heat transfer = 0.022 × 7.24(25+20)/5.0 × 10^-2 = 143.352 watt.
The block's velocity is determined as 10.03 m/s.
<u>Explanation:</u>
According to work energy theorem, the work done on an object is equal to the change in kinetic energy of the object.
So, work done = Kinetic energy
Thus, the velocity can be determined as
Velocity = 10.03 m/s.
So the block's velocity is determined as 10.03 m/s.
Answer: 87500J
Explanation:
Given that,
Power exerted by crane = 3,500 W
Time taken = 25 seconds
work done by crane = ?
Since power is the rate of work done per unit time, then power is workdone by the crane divided by the time taken.
i.e power = work / time
3,500 W = work / 25 seconds
Work = 3500W x 25 seconds
Work = 87500J
Thus, 87500 joules of work was done by the crane.
A. All living things and objects
Answer:
0.08kg
Explanation:
K.E = 1/2 mv^2
v = 970m/s
K.E = 3.9x 10^3J= 3900J
K.E = 1/2 mv^2
3900 = 1/2 m x 970x 970
3900 = 1/2 ×940900m
3900 = 470450m
m = 3900/470450 = 0.00828993516 = 0.008kg
