a) The change in momentum of the ball.
Note that the ball is initially at rest, i.e. u=0m/s.
?P=mv-mu=(0.65*15)-(0.65*0)=9.75kgm/s
b) The average force exerted on the ball.
F=m(v-u)/t =(9.75kgm/s)/0.03s)=325N
c) The displacement of the ball in 2 seconds.
The upward acceleration of the ball is negative 2m/s5.
Moraa orina answered the question on April 8, 2018 at 17:35
- 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)
- A particle moving with a velocity of 200m/s is brought to rest in 0.02s. What is the acceleration of the particle?(Solved)
A particle moving with a velocity of 200m/s is brought to rest in 0.02s. What is the acceleration of the
particle?
Date posted: April 8, 2018. Answers (1)
- A body moves 30m due east in 2seconds, then 40m due north in 4seconds. Determine its:a) Average speed.(Solved)
A body moves 30m due east in 2seconds, then 40m due north in 4seconds. Determine its:
a) Average speed.
Date posted: April 8, 2018. Answers (1)
- Explain why in water the meniscus in the capillary tube is higher than in the beaker while in the mercury, the meniscus in the capillary tube is lower than in the beaker(Solved)
Explain why in water the meniscus in the capillary tube is higher than in the beaker while in the mercury, the meniscus in the capillary tube is lower than in the beaker.
Date posted: April 8, 2018. Answers (1)
- A body covers a distance of 2m in 4seconds, rests for 2seconds and finally covers a distance of 90m in 6seconds. Calculate its average speed.(Solved)
A body covers a distance of 2 m in 4 seconds, rests for 2 seconds and finally covers a distance of 90 m in
6seconds. Calculate its average speed.
Date posted: April 8, 2018. Answers (1)
- State the dangers of Bernoulli’s effect(Solved)
State the dangers of Bernoulli’s effect
Date posted: April 8, 2018. Answers (1)
- Explain the applications of Bernoulli’s principle(Solved)
Explain the applications of Bernoulli’s principle
Date posted: April 8, 2018. Answers (1)
- A lawn sprinkler has 40holes each of cross-section area 2.0 x10-2cm2. It is connected to a horse pipe of
cross-section area 1.6cm2. if the speed...(Solved)
A lawn sprinkler has 40holes each of cross-section area 2.0 x10-2cm2. It is connected to a horse pipe of
cross-section area 1.6cm2. if the speed of water in the horse pipe is 1.2m/s, calculate:
a) The rate of flow in the horse pipe.
b) The speed at which water emerges from the holes.
Date posted: April 8, 2018. Answers (1)
- 600g of water flows through a tube of uniform cross-section area of 20 cm^2 in 10 s. If the density of water is 1000 kgm-3, calculate the...(Solved)
600g of water flows through a tube of uniform cross-section area of 20cm2 in 10s. If the density of water is 1000kgm-3, calculate the rate of flow of the water.
Date posted: April 8, 2018. Answers (1)
- Explain the three types of flow(Solved)
Explain the Three types of flow
Date posted: April 8, 2018. Answers (1)