Answer:
15? I actually don't know
Answer: 
Explanation:
Given
Length of plank is 1.6 m
Force
is applied on the left side of plank
Force
is applied 43 cm from the left end O.
Mass of the plank is 
for equilibrium
Net torque must be zero. Taking torque about left side of the plank

Net vertical force must be zero on the plank

Answer:
Zero
Explanation:
It is given that,
A person swims to the other end of a 20m long pool and back.
We need to find his displacement.
Displacement = shortest path covered
He reaches at the same position as from where he has started. It means the shortest path covered is equal to 0 i.e. his displacement is zero.
Answer:
Explanation:
Given
Ball of mass m
maximum Bearable Tension in string is F
Let length of the cord be L m and moving at a speed of v m/s
Here Tension will Provide Centripetal Force
T=Centripetal Force

