Answer:
So instantaneous velocity after 9 sec will be 88.2 m/sec
Explanation:
We have given time t = 9 sec
As the object is released from rest so its initial velocity u = 0 m/sec
We have to find its final velocity v
Acceleration due to gravity
From first equation of motion we know that
So instantaneous velocity after 9 sec will be 88.2 m/sec
Answer:
Total energy saving will be 0.8 KWH
Explanation:
We have given there are 50 long light bulbs of power 100 W so total power of 50 bulb = 100×50 = 5000 W = 5 KW
30 bulbs are of power 60 W
So total power of 30 bulbs = 30×60 = 1800 W = 1.8 KW
Total power of 80 bulbs = 1.8+5 = 6.8 KW
Total time = 3 hour
We know that energy
Now power of each CFL bulb = 25 W
So power of 80 bulbs = 80×25 = 2000 W = 2 KW
Energy of 80 bulbs = 2×3 = 6 KWH
So total energy saving = 6.8-6 = 0.8 KWH
Answer:
28.6260196842 m
Explanation:
Let h be the height of the building
t = Time taken by the watermelon to fall to the ground
Time taken to hear the sound is 2.5 seconds
Time taken by the sound to travel the height of the cliff = 2.5-t
Speed of sound in air = 340 m/s
For the watermelon falling
For the sound
Distance = Speed × Time
Here, distance traveled by the stone and sound is equal
The time taken to fall down is 2.4158 seconds
Height of the buidling is 28.6260196842 m