Q- Two particles executes SHM of same amplitude of 20 cm with same period along the same line and about same equilibrium position. If the maximum distance between them is 20 cm, find their phase difference.

### Projectile Motion

Q- A shall is fired from a hill of height ‘h’ at an angle of 45^{0}. What is the magnitude of its velocity of projection as a function of its horizontal distance covered on ground x, acceleration due to gravity g and height h?

### AC Circuits

Q- In an AC circuit the voltage across a resistive component is given by V(t) = 10 + 5 sin (3t). Find

(a) The voltage amplitude

(b) Root mean square voltage across the component Vrms.

### Thermodynamics: Refrigerator

Q- A household refrigerator that has a power input of 450W and a COP of 2.5 is to cool 5 large watermelons, 10 kg each, to 10^{o}C. If the melons are initially at 20^{o}C, determine how long it will take for the refrigerator to cool them. The specific heat of melons = 4.2 kJ/(kg.^{o}C)

### Work Done by Variable Force

Q- The force verses displacement graph for a variable force acting on a particle during some displacement is given bellow (the thick lines)

(a) Calculate the total work done by this force on the particle.

(b) Which well-known physical device could produce the type of force during the first 10 seconds? Explain