IDEAL INDIAN SCHOOL, DOHA - QATAR
CLASS 11 : WORKSHEET CHAPTER 5 - LAWS OF MOTION
1. Determine the tensions T1 and T 2 in the strings shown in the figure:
2. What is the acceleration of the block and trolley system shown in fig. if the coefficient of
kinetic friction between the trolley and the surface is 0.04? What is the tension in the string?
(Take g=10 ms 2 ). Neglect the mass of the string.
3. Three blocks are connected as shown below and are on a horizontal frictionless
table. They are pulled to right with a force F = 50 N. If m1 = 5 kg, m2 = 10 kg and m3
= 15 kg, calculate tensions T1 and T2.
4. A bend in a level road has a radius of 100 m. The coefficient of friction between the
tyres and the road is 0.8. Calculate the maximum speed of the car taking a sharp turn
without skidding.
5. A 3 kg ball strikes a heavy rigid wall with a speed of 10 m/s at an angle of 60ᵒ.
It gets reflected with the same speed and angle as shown here.
The ball is in contact with the wall for 0.20 s.
Calculate the average force exerted on the ball by the wall.
6. A stone of mass 0.25 kg tied to the end of a string is whirled
round in a circle of radius 1.5 m with a speed of 40 rev./min in a horizontal plane. What is
the tension in the string? What is the maximum speed with which the stone can be whirled
around if the string can withstand a maximum tension of 200 N?
7. A cyclist riding at a speed of 14√3 m/s takes a turn around a circular road of radius
20√3 m. Calculate the angle of inclination to the vertical.
8. A light string passing over a smooth light pulley, connects two blocks of masses m1
and m 2 such that m1 > m 2 (vertically ). If the acceleration of the system is g/ 8,
calculate the ratio of their masses.
9. A 30 kg shell is flying at a speed of 48 m/s. When it explodes, its one part of 18 kg
stops, while the remaining part flies on. Calculate the velocity of the latter part.
10. A body of mass 1 kg, initially at rest, explodes and breaks into three fragments of masses
in the ratio 1:1:3. The two pieces of equal mass fly off perpendicular to each other with a
speed of 30m/s each. What is the velocity of the heavier fragment?
11. A monkey of mass 40 kg climbs on a rope which can stand a maximum tension
of 600 N. In which of the following cases will the rope break. When the monkey (a) Climbs
up with an acceleration of 6 ms -2 (b) Climbs down with an acceleration of 4 ms -2 .
(c) Climbs up with a uniform speed of 5 ms -1. (d) Falls down the rope nearly freely under
gravity. (Ignore the mass of the rope)
12. A man of mass 70 kg stands on a weighing scale in a lift which is moving.
(a) Upwards with a uniform speed of 10 ms−1.
(b) Downwards with a uniform acceleration of 5 ms−2.
(c) Upwards with a uniform acceleration of 5 ms−2.
What would be the reading on the scale in each case?
(d) What would be the reading if the lift mechanism failed and it hurtled down freely under
gravity?
13. An aircraft executes a horizontal loop at a speed of 720 km/h with its wings banked
at 150. What is the radius of the loop? (Take tan 150 = 0.268 )
14. A train runs along an unbanked circular track of radius 30m at a speed of 54km/h. The
mass of the train is 10 6 kg. What provides the centripetal force required for this purpose-the
engine or the rails? What is the angle of banking required to prevent wearing out of the rail?
15. A steam of water flowing horizontally with a speed of 25 m/s gushes out of a tube of
cross-sectional area 10 -2 m 2, and hits a vertical wall nearby. What is the force exerted on the
wall by the impact of water ?
16. (a) A marble block of mass 2 kg lying on ice , when given a velocity of 6 m/s, is
stopped by friction in 10 s. Calculate the coefficient of friction.
(b) If the radii of circular paths of two particles of same masses are in the ratio of 1:2,
then to have a constant centripetal force, their velocities should be in the ratio ----------
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(c) Explain why (i) a horse cannot pull a cart and run in empty space (ii) a cricketer
moves his hands backwards while taking a catch
17. Two billiard balls each of mass 0.05kg moving in opposite directions with
speed 6ms−1collide and rebound with the same speed. What is the impulse imparted to each
ball due to the other?
18. A batsman deflects a ball by an angle of 450 without changing its initial speed which is
equal to 54 km/h. what is the impulse imparted to the ball? (mass of the ball is 0.15kg)
