P= 10m = 10 x 9.10 = 91 N
Work is done lifting a 9.10-kg box straight up onto a shelf that is 1.80 m high :
A= Ph = 91 x 1.80 = 163.8 J
ok done. Thank to me :>
Answer:
To achieve the velocity of 40 m/sec height will become 4 times
Explanation:
We have given initially truck is at rest and attains a speed of 20 m/sec
Let the mass of the truck is m
At the top of the hill potential energy is mgh and kinetic energy is 
So total energy at the top of the hill 
At the bottom of the hill kinetic energy is equal to
and potential energy will be 0
So total energy at the bottom of the hill is equal to 
Form energy conservation 
, for v = 20 m/sec

Squaring both side

h = 20.408 m
Now if velocity is 0 m/sec


h = 81.63 m
So we can see that to achieve the velocity of 40 m/sec height will become 4 times
Answer:
R = 5.73 m
Explanation:
For an angle of rotation through 21 degree we know that
arc length is given as

now we know that
Arc = 2.1 m
Angle = 21 degree

so now we have



a) An inflated balloon was pressed against a wall after it has been rubbed with a piece of synthetic cloth. It was found that the balloon sticks to the wall. <u>This is because a positive and negative electric charge is produced, therefore the balloon sticks to the wall.</u>
b) When an object is thrown up, it comes back to ground <u>because of gravitational attraction force of earth</u>.
c) Mountaineers suffer nose bleeding at higher altitudes <u>because the oxygen level decreases with increase in altitude, which the body cannot adjust.</u>
d) Foundations of high rise buildings are kept wide <u>because more is the area of contact, less is the pressure efforts. So, foundations are wide so as to decrease the possibility of the building from falling down.</u>
e) Deep sea divers or high altitude fliers wear special suits <u>so as prevent their body from being crushed by the water pressure. Since water pressure is maximum at deep seas and oceans, therefore, more is the risk of being injured.</u>
f) Walls of a dam are thickened near the base <u>so that the dam can handle the kinetic energy pressure and prevent itself from breaking down, which if not, can lead to flooding</u>.
HOPE IT HELPS...