**1.**The wheels of vehicles are provided with mudguards. Why?

**2.**Define spring constant of a spring?

**3.**What happens to the P.E of a bubble when it rises in water?

**4.**A light and a heavy body have same K.E. which of the two have more momentum and why?

**5.**The position x of a body of mass 2 kg varies with time t as x = (2t

^{2}+ 3t – 4) m.Find Force acting on the

body

**6.**A body of mass 2kg moving with a speed of 100 m/s hits a wall and rebounds with the same speed. If

the contact time is (1/50)s,Find the force
applied on the wall

**7.**

*A body dropped from a height H reaches the ground with a speed of*1.m/s2

*. Calculate the work done*

*by air-friction.*

**8.**A light string passes over a frictionless pulley. To one of its ends a mass of 6 kg is attached and

to its other end a mass of 10 kg is
attached. Find tension in the string .

**9.**A hunter has a machine gun that can fire 50g bullets with a velocity of 150 ms

^{–1}. A 60 kg tiger springs

at him with a velocity of 10 ms

^{–1}How many bullets must the hunter fire into the target so as to stop
him in his track?

**10.**A bullet of mass 0.01 kg is fired horizontally into a 4 kg wooden block at rest on a horizontal surface.

The coefficient of kinetic friction between the block and the surface is
0.25. The bullets gets

embedded in the block and the combination moves 20m before coming to
rest. With what speed

did the bullet strike the block?

**11.**You push your physics book 1.50 m along a horizontal tabletop with a horizontal push of 2.40 N

while the opposing force of friction is 0.600 N. How much work does
each of the following forces

do on the book: (a) your 2.40-N
push, (b) the friction force, (c) the
normal force from the tabletop,

and (d) gravity? (e) What is the net work done on the book?

**12.**Your job is to lift 30-kg crates a vertical distance of 0.90 m from the ground onto the bed of a

truck.(a) How many crates would you have to load onto the truck in1
minute for the average power

output
you use to lift the crates to equal 0.50
hp? (b) How many crates for an average power output

of
100 W

**13.**How does a perfectly inelastic collision differ from perfectly elastic collision? Two particles of

mass m1 and m2 having velocities
u

_{1}and u_{2}respectively make a head on collision. Derive the
relation for their
finalvelocities. Discuss the following special cases.

(i)
m1 = m2 (ii) m1 >> m2 and U2 = 0
(iii) m1 << m2 and u1 = 0

**OR**

The
blades of a windmill sweep out a circle of area A a) If the wind flows at a
velocity v perpendicular

to
the circle, what is the mass of the air passing through it in time t?

b)What is the kinetic energy of the air? (c)
Assume that the windmill converts 25% of the wind’s

energy into electrical energy, and that A = 30m

^{2}, v = 36km/hr and density of air is 1.2 kg m^{–3}. What is the electrical power produced?**14.**A disc revolves with a speed of 33 rev/min and has a radius of 15cmTwo coins are placed at 4

cm and 14 cm away from the centre of the
record. If the coefficient of friction between the coins

and the
record is 0.15, which of the coins will revolve with the record?

OR

**Why circular roads are banked? Derive an expression for maximum possible speed with which**

angle of banking is needed for safe circular turn