Advantages of friction
? Makes walking, writing possible.
? Required for braking in cars, bicycles etc.
? Makes rotation of the conveyor belts in factories possible.
? Necessary for lighting matchsticks.
? Useful when using nuts, bolts, screw jacks, vices etc.
Moraa orina answered the question on April 9, 2018 at 09:27
- A bullet of mass 2g travelling horizontally at 20m/s embeds itself in a block of wood of mass 990g suspended from a light inextensible...(Solved)
A bullet of mass 2g travelling horizontally at 20m/s embeds itself in a block of wood of mass 990g
suspended from a light inextensible string so that it can swing freely. Find:
The velocity of the bullet and block immediately after collision.
Date posted: April 9, 2018. Answers (1)
- A 5kg mass moving with a velocity of 2m/s collides with a 2kg mass moving at 7m/s along the same line.
If the two masses...(Solved)
A 5kg mass moving with a velocity of 2m/s collides with a 2kg mass moving at 7m/s along the same line.
If the two masses join together on impact, find their common velocity if they were moving:
a) In opposite directions.
b) In the same direction.
Date posted: April 9, 2018. Answers (1)
- . A bullet of mass 20g is shot from a gun of mass 20kg with a muzzle velocity of 200m/s. if the bullet is
30cm...(Solved)
A bullet of mass 20g is shot from a gun of mass 20kg with a muzzle velocity of 200m/s. if the bullet is
30cm long, determine:
a) The acceleration of the bullet.
b) The recoil velocity of the gun.
Date posted: April 9, 2018. Answers (1)
- Differentiate between elastic collision ana inelastic collision(Solved)
Differentiate between elastic collision ana inelastic collision
Date posted: April 9, 2018. Answers (1)
- A car of mass 1500kg is brought to rest from a velocity of 25m/s by a constant force of 3000N. Determine
the change in momentum...(Solved)
A car of mass 1500kg is brought to rest from a velocity of 25m/s by a constant force of 3000N. Determine
the change in momentum produced by the force and the time it takes the car to come to rest.
Date posted: April 9, 2018. Answers (1)
- Explain why the bristles of a paint brush cling together when removed from water in a bucket(Solved)
Explain why the bristles of a paint brush cling together when removed from water in a bucket.
Date posted: April 9, 2018. Answers (1)
- A man of mass 75kg stands on a weighing machine in a lift. Determine the reading on the weighing
machine when the lift:
a) Ascends with...(Solved)
A man of mass 75kg stands on a weighing machine in a lift. Determine the reading on the weighing
machine when the lift:
a) Ascends with an acceleration of 2m/s5.
b) Descends at a constant velocity of 1.5m/s
c) Descends with an acceleration of 5.5m/s5
Date posted: April 9, 2018. Answers (1)
- A man of mass 75kg stands on a weighing machine in a lift. Determine the reading on the weighing machine when the lift:a) Ascends...(Solved)
A man of mass 75kg stands on a weighing machine in a lift. Determine the reading on the weighing
machine when the lift:
a) Ascends with an acceleration of 2m/s5.
b) Descends at a constant velocity of 1.5m/s5.
c) Descends with an acceleration of 5.5m/s
Date posted: April 8, 2018. Answers (1)
- A kick that lasts 0.03s sends a ball of mass 0.65kg with a velocity of 15m/s northwards. Find:
a) The change in momentum of the...(Solved)
A kick that lasts 0.03s sends a ball of mass 0.65kg with a velocity of 15m/s northwards. Find:
a) The change in momentum of the ball.
b)the average force exerted on the ball.
c) The displacement of the ball in 2 seconds
Date posted: April 8, 2018. Answers (1)
- A ball of mass 35g travelling horizontally at 20m/s strikes a barrier normally and rebounds with a speed
of 3m/s. Find the impulse exerted on...(Solved)
A ball of mass 35g travelling horizontally at 20m/s strikes a barrier normally and rebounds with a speed
of 3m/s. Find the impulse exerted on the ball.
Date posted: April 8, 2018. Answers (1)
- Two stones of mass 8kg and 4kg move with velocities 3m/s and 6m/s respectively. Compare their momentum.(Solved)
Two stones of mass 8kg and 4kg move with velocities 3m/s and 6m/s respectively. Compare their
momentum.
Date posted: April 8, 2018. Answers (1)
- Jet fighter on practice moving at a velocity of 20m/s released a bomb above the ground which hits the ground after 3s. Calculate:a) the distance...(Solved)
Jet fighter on practice moving at a velocity of 20m/s released a bomb above the ground which hits the
ground after 3s. Calculate:
a) the distance from the ground to the jet,
b)the horizontal distance from the target when the bomb is released.
Date posted: April 8, 2018. Answers (1)
- A stone is thrown at a velocity of 30m/s to the horizontal by a girl at the top of a tree whose height is 30m....(Solved)
A stone is thrown at a velocity of 30m/s to the horizontal by a girl at the top of a tree whose height is 30m.
Calculate:
a) the time taken for the stone to strike the ground.
b) the velocity at which the stone strikes the ground.
Date posted: April 8, 2018. Answers (1)
- An object is released to fall vertically from a height of 20m. At the same time, another object is projected
vertically upwards with a velocity...(Solved)
An object is released to fall vertically from a height of 20m. At the same time, another object is projected
vertically upwards with a velocity of 40m/ss
a)Calculate the time taken before the two objects meet
b) At what height above the point of projection do they meet?
Date posted: April 8, 2018. Answers (1)
- A bullet is shot vertically upwards and rises to a maximum height of 200m. Calculate:
a)the initial velocity of the bullet,
b) the total time of flight.
(Solved)
A bullet is shot vertically upwards and rises to a maximum height of 200m. Calculate:
a)the initial velocity of the bullet,
b) the total time of flight.
Date posted: April 8, 2018. Answers (1)
- A hammer falls from the top of a building 5m high.
b) With what velocity does it strike the ground?(Solved)
A hammer falls from the top of a building 5m high.
b) With what velocity does it strike the ground?
Date posted: April 8, 2018. Answers (1)
- A hammer falls from the top of a building 5m high.
a) How long does it take to reach the ground? Take g=2ms-2
b) With what...(Solved)
A hammer falls from the top of a building 5m high.
a) How long does it take to reach the ground? Take g=2ms-2.
b) With what velocity does it strike the ground?
Date posted: April 8, 2018. Answers (1)
- A car travelling at 20m/s decelerates uniformly at 4m/s5. In what time will it come to rest?
v=u-at, (a is negative since the body is decelerating).(Solved)
A car travelling at 20m/s decelerates uniformly at 4m/s5. In what time will it come to rest?
v=u-at, (a is negative since the body is decelerating).
Date posted: April 8, 2018. Answers (1)
- An object accelerates uniformly at 3ms-5. It attains a velocity of 4m/s in 5seconds.
a) What was its initial velocity?
b)How far does it travel...(Solved)
An object accelerates uniformly at 3ms-5. It attains a velocity of 4m/s in 5seconds.
a) What was its initial velocity?
b)How far does it travel during this period?
Date posted: April 8, 2018. Answers (1)
- A particle travelling in a straight line at 2m/s is uniformly accelerated at 5m/s2 for 8seconds. Calculate the displacement of the particle.(Solved)
A particle travelling in a straight line at 2m/s is uniformly accelerated at 5m/s2 for 8seconds. Calculate the displacement of the particle.
Date posted: April 8, 2018. Answers (1)