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Syllabus
(a) Joule
(b) Horse Power
(c) Watt
(d) Pascal
Q.10. Fig. 3.18 below shows a wheel barrow of mass 15 kg carrying a load of 30 kgf with its centre of gravity at A. The points B and C are the centre of wheel and tip of the handle such that the horizontal distance AB = 20 cm and AC = 40 cm.
Find : (a) the load arm, (b) the effort arm, (c) the mechanical advantage, and (d) the minimum effort required to keep the leg just off the ground.
Ans. (a) 20 cm (b) 60 cm, (c) 3 (d) 15 kgf
Q4. The below figure shows the combination of a movable pulley P1 with a fixed pulley P2 used for lifting up a load W.
(i) State the function of the fixed pulley P2.
(ii) If the free end of the string moves through a distance x, find the distance by which the load W is raised.
(iii) Calculate the force to be applied at C to just raise the load W = 20 kgf, neglecting the weight of the pulley P1 and friction.
(Ans. changes direction, d2, F = 10 kgf) (ICSE 2005)
Long answer and with formula and diagram . no link
1. Velocity ratio of the jerk
2. Mechanical advantage of the jerk
3. Effort required in raising the body (g=10m/s, ?=22/7)
Q. The velocity time graph of a particle moving along a straight line in a given time interval is as shown in figure. Then the particle (with increase in time starting from t = 0 sec.)
(A) speeds up
(B) speeds down
(C) first speeds down and then speeds up
(D) first speeds up and then speeds down
Please send it fast. It is urgent
Q.3. A load of 800 N is to be lifted up a platform 3 m high using a ramp. If the length of the ramp is 15 m, find the effort required to push the load along the ramp onto the platform.
[Ans. 160 N]
Q62. The horizontal range of a bullet fired with angle of projection 45° to the horizontal is 360 m. If it is fired from a lorry moving in the direction of bullet with the uniform velocity 18 km hr–1 and with same elevation, what is the new range horizontal distance traveled by the bullet? (Take g = 10 ms–2).
3. A force of 5 kgf is required to cut a metal sheet. A shears used for cutting the metal sheet has its blades 5 cm long, while its handles are 10 cm long. What effort is needed to cut the sheet?
displacement of 0.15 m. The load of mass 10 kg is raised up by 10 cm. Calculate
M.A, VR, Work input, useful work output and efficiency. (g = 10m/s
2
)
6. A uniform metre scale is kept in equilibrium when supported at the 60 cm mark and a mass M is suspended from the 90 cm mark as shown in the figure. State with reasons whether the weight of the scale is greater then less than or equal to the weight of mass M.
Thank you
62. The horizontal range of a bullet fired with angle of projection 45° to the horizontal is 360 m. If it is fired from a lorry moving in the direction of bullet with the uniform velocity 18 km hr−1 and with same elevation, what is the new range horizontal distance travelled by the bullet? (Take g = 10 m s−2).
Q.5. A pulley system has a velocity ratio of 4 and efficiency of
90 %. Calculate:
(i) the mechanical advantage of the system,
(ii) the effort required to raise a load of 300 N by the system.
(Ans. 3.6, 83.33 N)
Q5. A man uses a crowbar of length 1.5 m to raise a load of 75 kgf by putting a sharp edge below the bar at distace of 1 m from his hand. (a) Draw a diagram of the arrangement showing the fulcrum (F), load (L) and effort (E) with their directions, (b) State the kind of leaver. (c) Calculate : (i) load arm, (ii) effort arm, (iii) mechanical advantage, and (iv) the effort needed.
Ans. (b) class I (c) (i) 0.5 m (ii) 1.0 m (iii) 2 (iv) 37.5 kgf.
Q6. A pair of scissors is used to cut a piece of a cloth by keeping it at a distance of 8-0 cm from its rivet and applying an effort of 10 kgf by fingers at a distance of 2.0 cm from the rivet.
(a) Find : (i) the mechanical advantage of scissors, and (ii) the load offered by the cloth.
(b) How does the pair of scissors act : as a force multiplier or as a speed multiplier?
Ans. (a) (i) 0.25 (ii) 2.5 kgf. (b) Speed multiplier
11. A pulley system has five pulleys in all and is 75% efficient. Calculate
(a) MA
(b) an effort required to lift a load of 1875 N
(c) the resistance due to movable parts of the pulley system.
Single-fixed pulley system
Single-movable pulley system
Sheaf pulley systemor block and tackle system of pulleys