The bob of a simple pendulum of length 1 m is' pulled aside from its equilibrium’ position through an angle `60^@` and released. Calculate the speed at which the bob passes the equilibrium position.

The bQB of a pendulum is released from a horizontal position. If the length of the pendulum is 1.5 m, what is the speed with which the bQB arrives at the lowermost point, given that it dissipated 5% of its initial energy against air resistance?

Two springs are connected in parallel as shown. If the mass is displaced from its equilibrium position and released. What is the resultant frequency of vibration?

The time period of a simple pendulum is 4.25. When its length is decreased by 1m its period is 3.75. Find the original length of the pendulum.

A simple pendulum of length I and mass m is suspended in a car that is travelling with a constant speed v around a circle of radius R. If the pendulum undergoes small oscillations about its equilibrium position, what will be its frequency•of oscillation ?

A simple pendulum with a negatively charged bob is made to oscillate just above a positively charged plate. What happens to its time period?

When a telephone post is broken by a strong wind,its top touches the ground 3 metres a part from the base making an angle 60^@ .Find the height of the post and also the position at which the post is broken.

A man standing on the deck of a ship which is 10 m above the water level, observes the angle of elevation of the top of a hill as 60° and angle of depression of the base of a hill as 30°. Calculate the distance of the hill from the ship and the height of the hill.

The distance between two poles of the same height standing on the same plane is 100m.The angles of elevation of the tops of the two poles from a point lying on the line joining the base-points of the poles are found to be 30^@ and 60^@ respectively.Find the heights of the poles and the position of the point.

An aeroplane flying horizontally at a height of 1.5 km above the ground is observed at a certain point on the earth to subtend an angle 60°. After 15 second its angle of elevation is observed to be 30°. Calculate the speed of aeroplane in Km/h.

Write down the equation of the straight line passing through the origin which makes an angle 60^@ with positive x-axis.