Question 6
An object is to be lifted from the ground to a height of 5m in 25 seconds. If the energy consumed
during the process is 2000 J, what is the power required?
A.
75 J/s
B.
72 J/s
C.
80 J/s
D.
100 J/s
E.
125 J/s
Correct Answer: C
Explanation:
Power is given as
P = W/t ---------------- (1)
Putting the values in equation 1 we get
P = 2000 / 25
P = 80 J/s or Watt
Hence, C is the correct answer option.
Question 7
A block of mass M, connected to a spring of spring constant k (a spring-mass system), is executing
SHM with time period, T on Earth. If the same system executes SHM on the surface of Moon, what
will be the new time period?
A.
More than that on the Earth
B.
Less than that on the Earth
C.
Same as that on the Earth
D.
Zero
E.
Not enough data is provided to predict the answer
Correct Answer: C
Explanation:
Time period is given as
T = 2π √(M/k) ---------------- (1)
At the surface of the Moon, acceleration due to gravity is (1/6)th of that on the surface of the Earth.
As, there is no term related to acceleration due to gravity in equation 1, time period of the system
will remain unaffected. Hence, time period of the system on the moon will be the same as that of
the system on the Earth. Therefore, C is the correct answer option.
