Answer:
12500W
Explanation:
Given parameters:
Work done = 250000J
Time taken = 20s
Unknown:
Power of the crane = ?
Solution:
Power is the defined as the rate at which work is being done;
Mathematically;
Power = 
insert the parameters and solve;
Power = 
= 12500W
Answer:
Option c
Explanation:
Magnetic field lines form loops starting from north pole to south pole outside the magnet and from south pole to north pole inside the magnet.
Thus the field is such that it is directed outwards from the North pole and directed inwards to the South pole of the magnet.
A compass in a magnetic field will will comply with the magnet's North pole directing towards the magnetic field.
Answer:
He requires 1 gram of mass.
Explanation:
The density is defined as:
(1)
Where m is the mass and V is the volume.
Then, m can be isolated from equation 1 in order to determine the mass.
(2)
Hence, he requires 1 gram of mass.
Answer:
F= 25/2 = 12.5N
Explanation:
When you use a compound pulley the force required depends on the mechanical advantage of the compound pulley. This is known as rate of loss of distance or the ratio of the force to the load.
M.A = Effort distance /Load distance. OR M.A = Load/Effort
