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This question is about forces and moments of forces.
a. (I) Define the moment of a force about a point
(II) State the law of moments as a condition for equilibrium
b. A crane has a jib (AC) of mass 2500kg pivoted at A.
The jib is supported by a horizontal cable BC. The centre of mass of the jib its at D. The dimensions are as shown on the diagram.
(I) Make a sketch copy of the diagram and on it draw three arrows to represent the three forces acting on the jib.
(ii) Calculate the tension in the cable BC.
C. The end of the jib C is raised by shortening BC. Explain whether the tension in BC will increase or decrease.
SA1. A pebble is projected vertically upward using a sling shot at a velocity of 50.0 m/s. What is its velocity at a height of 2.0 m?
SA2. At what height of the flight of the pebble in SA1 shall it have a velocity of 12.0 m/s?
SA3. How long shall the pebble in SA1 attain a velocity of 0.0 m/s?
SA4. Where shall the pebble in SA1 be located 4.0 seconds after it was launched?
SA5. How far shall the pebble in SA1 be from its point of origin at the time described in SA4?
SA6. A ball is projected vertically upward at a velocity of 15.0 m/s. At what position shall it be located at a velocity of – 10.0 m/s?
A chopper drops boxes of relief goods to a group of people stranded in an island. The goods were released 20.0 m above the sea and landed 40.0 m from a point exactly below where the goods were released. What was the velocity of the goods when they were released? What was the velocity of the chopper?
A plane flying 30.0 m above the sea at a velocity of 100.0 m/s along the horizontal will drop relief goods to people who are stranded in an island. When shall the goods be released so that they fall exactly where the people are located? Prove your answer through your solution.
A volleyball player hits the ball 40 cm above the top of the net towards his opponents’ court at a velocity of 15.0 m/s along the horizontal. If the top of the net is 2.0 m high from the floor and the length of the opponents’ court is 9.0 m, will the volleyball land within the opponents’ court? Why?
A bike successfully made a turn around a circular path whose radius is 13 m. At what angle is the road banked if it’s velocity was 12.0 m/s?
A turkish composite bow can release an arrow with a speed of 100 m/s.
(a) if a turk were to fire the bow at 10 degrees above the horizontal in order to hit someone lying 5 metres below him, if air resistance is negligible, what would be:
(i) the time taken?
(ii) the horizontal distance x?
(b) repeat the above calculations assuming vertical air resistance is negligible, but horizontally it causes a deceleration of 0.5 m/s2.
A proton traveling at 107m/s Collides with a stationary particle and bounces back add 2×2 is collides with a stationary particle and bounces back at 2*10^6m/s. If the Particles moves forward at 3*10^6. Find the mass of the station iPad scree find the mass of the stationary Particle
A body of mass 4kg moving with a velocity of 7m/s is acted upon by a force of 20N for 0.1s. Determine the final velocity of the body
a car is traveling on a straight road at 19 m/s. the driver sees a bird standing in the road 38 meters ahead and applies the brakes, giving constant deceleration of 5 m/s2.
(a) how far away is the driver from the bird when he stops? ( assuming the bird doesn't move)
(b) how long does it take the driver to stop?
(c) the driver was in a 40 miles per hour zone. given that there are approximately 1.6 km in 1 mile, was the driver speeding?
