Answer:
e). 
Explanation:
As we know that wheel is turned by 90 degree angle
so the angular speed of the wheel is given as

now we have


now the centripetal acceleration of the point P is given as



tangential acceleration is given as



now net acceleration is given as



Answer:
Mumbai
Explanation:
Because Mumbai is a coastal city
due to high humidity,vigorous rusting damages all the iron structures
∴ rusting is a major problem in Mumbai
Gravitational potential energy =
(mass) x (gravity) x (height)
= (5.8 kg) x (9.8 m/s²) x (2.5 m)
= 142.1 Joules (C)
Answer:
Time taken, 
Explanation:
It is given that, a small metal ball is suspended from the ceiling by a thread of negligible mass. The ball is then set in motion in a horizontal circle so that the thread’s trajectory describes a cone as shown in attached figure.
From the figure,
The sum of forces in y direction is :


Sum of forces in x direction,

.............(1)
Also, 
Equation (1) becomes :

...............(2)
Let t is the time taken for the ball to rotate once around the axis. It is given by :

Put the value of T from equation (2) to the above expression:


On solving above equation :

Hence, this is the required solution.