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Syllabus
Q. A U - shaped uniform wire of sides 2l, l and l. The x and y co-ordinates of the centre of mass of each side are shown in figure.
Q. A bomb of mass 'm' at rest at the coordinate origin explodes into three equal pieces. At a certain instant one piece is on the x-axis at x = 40 cm and another is at x = 20 cm, y = 60 cm. The position of the third piece is
1) x = 60 cm, y = 60 cm 2) x = 60 cm, y = 60 cm
3) x = 60 cm, y = 60 cm 4) x = 60 cm, y = 60 cm
Q.9. Draw a velocity-time graph for a body moving with an initial velocity u and uniform acceleration a. Use this graph to find the distance travelled by the body in time t.
Q. Three identical bricks each of length L are placed as shown in fig. The centre of mass of the system is from O at a distance of
NOTE: It must be only in the form of table and in 4 points
21. The acceleration of a moving body is constant in magnitude and direction. Must the path of the body be a straight line? If not, give an example.
Q.10. One litre of water is added to one litre of milk. What will be the density of the mixture? Given 1 litre 1000 and density of milk is 1.04 g/.
[Ans. 1.02 g/]
Q14. A space craft flying in a straight course with a velocity of 75 km s–1 fires its rocket motors for 6.0 s. At the end of this time, its speed is 120 Km s–1 in the same direction. Find : (i) the space craft's average acceleration while the motors were firing, (ii) the distance travelled by the space craft in the first 10 s after the rocket motors were started, the motors having been in action for only 6.0 s.
Ans. (i) 7.5 Km s–2, (ii) 1065 Km
Q15. A train starts from rest and accelerates uniformly at a rate of 2 m s–2 for 10 s. It then maintains a constant speed for 200 s. The brakes are then applied and the train is uniformly retarded and comes to rest in 50 s. Find : (i) the maximum velocity reached, (ii) the retardation in the last 50 s, (iii) the total distance travelled, and (iv) the average velocity of the train.
Ans. (i) 20 m s–1, (ii) 0-4 m s–2, (iii) 4600 m, (iv) 17.69 m s–1
a.Spring Equinox and Autumn Equinox
b.Perihelion and Aphelion
Q). A system consists of mass 5 gm, 10 gm and 15 gm located at and (1, 5, - 3), (2, 5, 7) and (3, 3, - 1) respectively. Then position of centre of mass of the system is
1) x-cordinate of the centre of mass is 7 / 3.
2) y-cordinate of the centre of mass is 4.
3) z-cordinate of the centre of mass is 4 / 3.
4) x-cordinate of the centre of mass is 3 / 7.
3. A body is moving in a straight line and its displacement at various instants of time is given in the following table
Plot displacement - time graph and calculate
(i) total distance travelled in 1 s 5 s.
(ii) average velocity in time interval 1 s to 5 s.
1. A body starts from rest with a uniform acceleration 2 m s-2. Find the distance covered by the body in 2 s.
2. A body starts with an initial velocity of 10 m s-1 and acceleration 5 m s-2. Find the distance covered by it in 5 s.
B-112 A body is projected horizontally from the top of a tower with initial velocity 18 ms-1 , it hits the ground at angle 45o. What is the vertical of velocity when it strikes the ground ?