Answer:
D
Explanation:
D) The overall work done by gravity is zero
This statement is correct .
If m be the mass of each of the children and h be the height of tower
work done by gravity on the boys in going up = - mgh
it is so because force applied by gravity = mg downwards and displacement
is upwards
work done will be negative = - mgh
Work done by gravity on boys when they come down = + mgh because both force and displacement are downwards .
Hence total work done = - mgh + mgh = 0.
The children will have same kinetic energy as the inclined surface is friction-less so no energy will be dissipated hence addition of energy to boys in both the cases will be same.
a = acceleration of the bank cart = 4 m/s²
m = mass of the bank cart = 8000 kg
F = net force on the cart
According to newton's second law , Net force is the product of mass of the object and the acceleration of the object.
Net force = mass x net acceleration
hence Net force acting on the cart is given as
F = ma
F = 8000 x 4
F = 32000 N
hence the net force acting on the cart comes out to be 32000 N
decomposition
A decomposition reaction is just the opposite of combination reaction
Answer:
2400 km
Explanation:
30km for 1hr
Need up to 80 hrs , multiply both 80 and 30
So its 2400km
