Answer:
option (A)
Explanation:
The a body having rest mass is mo is moving with velocity v which is of the order of velocity of light in vacuum, so the mass of the body increases. According to the formula

As the velocity increases, the mass m of the body increases. As the velocity of the object is equal to the velocity of light in vacuum, then the mass of the body becomes infinite.
This is the reason why dimensional analysis is very important. It is a technique used that only involves operations with units. You disregard the quantities first. The concept is to make sure that the final answer of your calculations must be consistent of what is asked. Similar units are cancelled when they appear both on the numerator and denominator side. If the mathematicians used this, they could've prevented the crash from happening. What good would the calculations bring if you are not consistent with the units?
Answer:
Explanation:
magnetic field B = (3 i + 8 x 2 j )x 10⁻³ T
= (3 i + 16 j )x 10⁻³ T
L = - i ( unit length of conductor )
Force F = I ( L x B ) , I is current
= 5 [ - i x ( 3i + 16 j ) 10⁻³]
= 5 ( - 16 k ) x 10⁻³
F = - 80 x 10⁻³ k
Positive - Friction allows us to create heat in a desperate situation, like being lost in the woods. If we didn't have friction, we would probably freeze to death.
Negative - Friction can also cause unwanted fires, such as forest fires. If friction didn't exist, we wouldn't have these.