Answer:
The time taken is missing in the question. The time is 18 minutes.
The answer is 34.3 km/hr
Explanation:
Average velocity is the speed or the velocity which is required to cover a distance in a time interval.
The time taken is = 18 min
= 18/60 hours
The distance from the university to her home is = 10.3 km
Therefore, the average velocity is = displacement/time taken
= 10.3 / (18/60) km/hr
= 34.3 km/hr
Hence, the average velocity is 34.3 km/hr
Answer:
Explanation:
a )
one kg of coal gives energy of 27 x 10⁶ J
75 kg of coal gives energy of 27 x 10⁶ x 75 J
So rate which energy is coming out of coal per second
= 27 x 10⁶ x 75 J
= 2025 x 10⁶ J /s
2025 million watts .
b ) energy output = 800 million watts
efficiency = (800 / 2025) x 100
= 39.5 % .
Answer:
Change in kinetic energy is ( 26CL³)/3
Explanation:
Given :
Net force applied, F(x) = Cx² ....(1)
Displacement of the particle from xi = L to xf = 3L.
The work-energy theorem states that change in kinetic energy of the particle is equal to the net amount of work is done to displace the particle.
That is,
ΔK = W = ∫F·dx
Substitute equation (1) in the above equation.
ΔK = ∫Cx²dx
The limit of integration from xi = L to xf = 3L, so
Substitute the values of xi and xf in the above equation.
Answer:
h=20.66m
Explanation:
First we need the speed when the cord starts stretching:
This will be our initial speed for a balance of energy.
By conservation of energy:
Where
is your height at its maximum elongation
is the height of the bridge
is the length of the unstretched bungee cord
Solving for h:
and 
Since 99m is higher than the initial height of 79m, we discard that value.
So, the final height above water is 20.66m
