Types of Forces

A monkey of mass $20 \mathrm{kg}$ is holding a vertical rope. The rope will not break when a mass of $25 \mathrm{kg}$ is suspended from it but will break if the mass exceeds $25 \mathrm{kg}$. What is the maximum acceleration with which the monkey can climb up along the rope? $\left(g=10 \mathrm{m} {\mathrm{s}}^{-2}\right)$

Two blocks of mass $2.9 \mathrm{kg}$ and $1.9 \mathrm{kg}$ are suspended from a rigid support $S$ by two inextensible wires each of length $1 \mathrm{m}$ see figure. The upper wire has negligible mass and the lower wire has a uniform mass of $0.2 \mathrm{kg}{\mathrm{m}}^{-1}$ . The whole system of blocks, wires and support has an upward acceleration of $0.2 \mathrm{m}{\mathrm{s}}^{-2}$ . Acceleration due to gravity is $9.8 \mathrm{m}{\mathrm{s}}^{-2}$ .

(i) Find the tension $T$ at the mid-point of the lower wire.

(ii) Find the tension  $T^{\text{'}}$  at the mid-point of the upper wire.

The bob of a $0.2 \mathrm{m}$ long pendulum describes an arc of circle in a vertical plane. If the tension in cord is $\sqrt{3}$ times the weight of the bob when cord makes an angle of $30°$ to the vertical, then acceleration of bob in that position is

Electric as well as gravitational affects can be thought to be caused by fields. Which of the following is true for an electrical or gravitational field?

Which one of the following is not a contact force?

What is strong and weak force?

An elevator of mass $1000 \text{kg}$ is moving upwards at a speed of $8 \text{m/s}$. It is brought to rest in a distance of $16 \text{m}$. Find the tension in the supporting cable and the force exerted by a man of mass $60 \text{kg}$ inside the elevator, on the floor. $\left(g=10 {\text{m/s}}^2\right)$

An elevator has a mass of $4000 \text{kg}$. What is the acceleration of the elevator in SI unit when the tension in the supporting cable is $48000 \text{N}$? $[g=10 {\text{m/s}}^2]$

In an elevator, a man of mass $80 \text{kg}$ stands on a spring balance. When it starts to move, the scale reads $700 \text{N}$. Calculate the acceleration of the elevator in ${\text{m/s}}^2$.

What was the temperature of the universe during the time of Big Bang ?

Who unified the weak force and the electromagnetic force?

Name the particle responsible for gravitational interaction.

Name the particle responsible for electromagnetic interaction.

Name the strongest and the weakest force.

What is the basic mechanism causing the interaction between particles ?

What are the fundamental forces ?

Name the different forces in nature.