After touching, the pith balls share the charge and become negative hence they repel.
sharon kalunda answered the question on April 4, 2019 at 09:09
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The length of a pinhole camera is 20cm. Determine the height of a storey building 300m away
from the pin hole if the image formed on...
(Solved)
The length of a pinhole camera is 20cm. Determine the height of a storey building 300m away
from the pin hole if the image formed on the screen of the pin hole camera is 2.5cm high
Date posted:
April 4, 2019
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Answers (1)
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Explain why transformers are widely used throughout the national grid system
(Solved)
Explain why transformers are widely used throughout the national grid system
Date posted:
April 4, 2019
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Answers (1)
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A coil of wire is connected in series with a battery, a rheostat and a switch as shown in figure
(Solved)
A coil of wire is connected in series with a battery, a rheostat and a switch as shown in figure
(i) Draw on the diagram, the shape of the magnetic field inside and outside the coil when the
switch is closed.
If the jockey J on the rheostat is moved towards Q what’s the effect on:-
(ii)The resistance of the circuit
(iii) The current through the coil
(iv) The magnetic field in the coil
Date posted:
April 4, 2019
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Answers (1)
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A student hung a magnet next to a coil of wire to make a door chime as shown in figure :-
(Solved)
A student hung a magnet next to a coil of wire to make a door chime as shown in figure :-
i) Explain how the current made the magnet move towards the chime bar
(ii) What should the student do to make the magnet hit the chime bar harder?
Date posted:
April 4, 2019
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Answers (1)
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The current capacity of an accumulator is 40Ah. Find the amount of current flowing if the
accumulator is used for 600 minutes
(Solved)
The current capacity of an accumulator is 40Ah. Find the amount of current flowing if the
accumulator is used for 600 minutes
Date posted:
April 4, 2019
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Answers (1)
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In the diagram below, the U-tube contains two liquids; X and Y which do not mix. If the density
of liquid Y is 900Kgm-3 and that...
(Solved)
In the diagram below, the U-tube contains two liquids; X and Y which do not mix. If the density
of liquid Y is 900Kgm-3 and that of X is 1200Kgm-3, calculate the height of liquid Y
Date posted:
April 4, 2019
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Answers (1)
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The figure below shows two mini buses A and B at a speed of 40m/s and 20m/s
respectively moving in opposite directions. They collided head on
(Solved)
The figure below shows two mini buses A and B at a speed of 40m/s and 20m/s
respectively moving in opposite directions. They collided head on
Determine the common speed of the vehicles if they stuck to each other
Date posted:
April 4, 2019
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Answers (1)
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A footballer kicks a ball of 600g initially at rest using a force of 900N. If the foot was in
contact with the ball for 0.1sec....
(Solved)
A footballer kicks a ball of 600g initially at rest using a force of 900N. If the foot was in
contact with the ball for 0.1sec. What was the take off speed of the ball?
Date posted:
April 4, 2019
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Answers (1)
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State the law of inertia
(Solved)
State the law of inertia
Date posted:
April 4, 2019
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Answers (1)
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A minibus of mass 2000kg traveling at a constant velocity of 36km/h collides with a stationary
car of mass 1000kg. The impact takes 2 seconds before...
(Solved)
A minibus of mass 2000kg traveling at a constant velocity of 36km/h collides with a stationary
car of mass 1000kg. The impact takes 2 seconds before the two move together at a constant
velocity for 20 seconds. Calculate:
(i) The common velocity
(ii) The distance moved after impact
(iii) The impulse force
(iv) The change in kinetic energy
Date posted:
April 4, 2019
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Answers (1)
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(i) complete the diagram below to show how the pulley can be used to raise a load L by
applying an effort E
(Solved)
(i) complete the diagram below to show how the pulley can be used to raise a load L by
applying an effort E
(ii) The pulley system above has a mechanical advantage of 3. Calculate the total work done
when a load of 60N is raised through a height of 9M
Date posted:
April 4, 2019
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Answers (1)
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A hydraulic machine is used to raise a load of 100kg at a constant velocity through a height
of 2.5m. The radius of the effort piston...
(Solved)
A hydraulic machine is used to raise a load of 100kg at a constant velocity through a height
of 2.5m. The radius of the effort piston is 1.4cm while that of the load piston is 7.0cm. Given
that the machine is 80% efficient, calculate:-
(i) The effort needed
(ii) The energy wasted in using the machine
Date posted:
April 4, 2019
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Answers (1)
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Name one machine that has a velocity ratio of less than one (V.R < 1)
(Solved)
Name one machine that has a velocity ratio of less than one (V.R < 1)
Date posted:
April 4, 2019
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Answers (1)
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The figure below shows a pulley system being used to raise a load.
(Solved)
The figure below shows a pulley system being used to raise a load.
If a load of 100N is raised by applying an effort of 48N, determine the efficiency of
the system.
Date posted:
April 4, 2019
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Answers (1)
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Vicky performed an experiment using a pulley system as shown in the figure.
(Solved)
Vicky performed an experiment using a pulley system as shown in the figure.
(a) What is the V.R. of the system?
(b) Determine the M.A. of the system. *
(c) Calculate the efficiency of the system.
(d) Explain why efficiency of a practical machine is always less than 100%
(e) If the load moves a distance of 5 cm. Find the work done on the load.
Date posted:
April 4, 2019
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Answers (1)
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An inclined plane of length 5m is used to raise a body of mass 60kg to the back of a lorry. If the
plane is inclined...
(Solved)
An inclined plane of length 5m is used to raise a body of mass 60kg to the back of a lorry. If the
plane is inclined at an angle 25° from the horizontal, calculate the efficiency of the system given
that a constant force of 650 N is used to push the body up the plane
Date posted:
April 4, 2019
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Answers (1)
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Sketch a velocity-time graph for a body moving with zero acceleration
(Solved)
Sketch a velocity-time graph for a body moving with zero acceleration
Date posted:
April 4, 2019
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Answers (1)
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State the three equations of linear motion.
(Solved)
State the three equations of linear motion.
Date posted:
April 4, 2019
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Answers (1)
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A car is traveling uniformly at 100km/hr when the driver observes a road block ahead.
He takes 0.5 s before applying the brakes which brings the...
(Solved)
A car is traveling uniformly at 100km/hr when the driver observes a road block ahead.
He takes 0.5 s before applying the brakes which brings the car to rest with a uniform
deceleration of 4m/s2. Determine the distance traveled by the car from the time the driver
observed the road block until the car comes to rest.
Date posted:
April 4, 2019
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Answers (1)
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In an experiment on momentum, trolley P of mass 800g was attached to a ticker timer of
frequency 50Hz. Trolley P, initially moving with a velocity...
(Solved)
In an experiment on momentum, trolley P of mass 800g was attached to a ticker timer of
frequency 50Hz. Trolley P, initially moving with a velocity of 0.5m/s, was made to collide
with a stationary trolley Q of mass 400g. A copy of the tape as it appeared after the collision is
presented in the figure below:-
a) Determine the velocity of the trolley P after collision
(b) Calculate the impulsive force experienced by trolley P
Date posted:
April 4, 2019
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Answers (1)