(i) Why must the tube be made of thin glass?
To equalize the temperature inside with that to the surrounding air.
(ii) Assuming that the weight of the pellet is negligible, what will the
pressure of the trapped air be when the tube is vertical? Explain.
Atmospheric pressure. For the pellet to remain at the position, the
pressure exerted by air should equal to the pressure outside.
Kavungya answered the question on June 4, 2019 at 08:05
- The Figure below shows a velocity-time graph for a steel ball falling
through a viscous fluid.
Explain the nature of the curve in;
(i) section PQ.
(ii) section QR.
(iii)...(Solved)
The Figure below shows a velocity-time graph for a steel ball falling
through a viscous fluid.
Explain the nature of the curve in;
(i) section PQ.
(ii) section QR.
(iii) If the graph shown above is of a ball falling through water, sketch on the same axis a graph for the ball falling through glycerine.
Date posted: June 4, 2019. Answers (1)
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The Figure 11 below shows a hydraulic lift supporting a load of 150kg. Its cross-sectional areas A1 and A2 are 0.02m2 and 0.4m2 respectively. The length of the effort arm is 1m and the length of the plunger from the pivot is 0.4m.
Determine:
(i) the pressure exerted by 150kg mass.
(ii) the pressure exerted by F1 on the smaller piston.
(iii) the force F1.
(iv) the applied force, Fe.
(v) the mechanical advantage.
(vi) the velocity ratio of the system.
(v) the efficiency of the system.
Date posted: June 4, 2019. Answers (1)
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A stone of mass 0.5kg is attached to a string of length 0.5m which will break if the tension exceeds 20N. The stone is whirled in a vertical plane, the axis of rotation being above the ground, as shown in the Figure below.
The angular velocity is gradually increased until the string breaks.
(a) In what position is the string most likely to break?
(b) At what angular velocity, w, will the string break?
Date posted: June 4, 2019. Answers (1)
- A stone is thrown with a horizontal velocity u from the top of a building of height 125m so as to hit a target on...(Solved)
A stone is thrown with a horizontal velocity u from the top of a building of height 125m so as to hit a target on the ground 75m from the base of the building as shown in Figure below.
Calculate:
(i) the time taken for the stone to hit the target.
(ii) the horizontal velocity, u, of the stone.
Date posted: June 4, 2019. Answers (1)
- The Figure below shows a planet Venus orbiting the sun in a circular orbit
at constant speed.
(i) State what provides the centripetal force.
(ii) Indicate the...(Solved)
The Figure below shows a planet Venus orbiting the sun in a circular orbit
at constant speed.
(i) State what provides the centripetal force.
(ii) Indicate the direction of centripetal force on the planet.
Date posted: June 4, 2019. Answers (1)
- Explain how greenhouse effect increase the average temperate of the earth.(Solved)
Explain how greenhouse effect increase the average temperate of the earth.
Date posted: June 4, 2019. Answers (1)
- The bicycle pump shown in Figure below is one of the applications of pressure in
gases.
Explain how the leather washer functions during;
(a) backstroke
(b) forward stroke(Solved)
The bicycle pump shown in Figure below is one of the applications of pressure in
gases.
Explain how the leather washer functions during;
(a) backstroke
(b) forward stroke
Date posted: June 4, 2019. Answers (1)
- The diagram below shows a spiral spring when not compressed and when
compressed by a mass of 4.0kg.
Determine the elastic potential energy stored by the compressed...(Solved)
The diagram below shows a spiral spring when not compressed and when
compressed by a mass of 4.0kg.
Determine the elastic potential energy stored by the compressed spring in (b).
Date posted: June 4, 2019. Answers (1)
- A smooth wooden plane is inclined at an angle of 300 to the horizontal as shown in Figure 5 below. An object of mass 10kg...(Solved)
A smooth wooden plane is inclined at an angle of 300 to the horizontal as shown in Figure 5 below. An object of mass 10kg is pulled steadily up the plane by a force of 60N. Determine;
(a) the velocity ratio of the inclined plane.
(b) efficiency of the system.
Date posted: June 4, 2019. Answers (1)
- The figure below shows a rubber bladder filled with air and fixed at the bottom of a
water container and held with a cotton string.
State and...(Solved)
The figure below shows a rubber bladder filled with air and fixed at the bottom of a
water container and held with a cotton string.
State and explain the observation made when water is heated gently for a few
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Date posted: June 4, 2019. Answers (1)
- An immersion heater consumes a voltage of 240V and a current of 10A. If it is used to heat 5kg of water at 200C, find...(Solved)
An immersion heater consumes a voltage of 240V and a current of 10A. If it is used to heat 5kg of water at 200C, find the final temperature of water after 7 minutes. (Take the specific heat capacity of water = 4200 J/kgk)
Date posted: June 4, 2019. Answers (1)
- A student observed some pollen grains on the surface of water in a beaker with the
help of hand lens as shown below.
(a) State the observation...(Solved)
A student observed some pollen grains on the surface of water in a beaker with the
help of hand lens as shown below.
(a) State the observation made.
(b) Explain the observation in (a) above.
(c) What conclusion can be drawn from the above experiment.
Date posted: June 4, 2019. Answers (1)
- A uniform bar is pointed at a point 30cm from one end. A force of 12N at the shorter
end keeps the bar in equilibrium. If...(Solved)
A uniform bar is pointed at a point 30cm from one end. A force of 12N at the shorter
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weight w, of the bar.
Date posted: June 4, 2019. Answers (1)
- The figure below shows a force of 40N acting on a body of mass 4kg. The coefficient of friction between the surfaces is 0.05.
Determine the...(Solved)
The figure below shows a force of 40N acting on a body of mass 4kg. The coefficient of friction between the surfaces is 0.05.
Determine the acceleration of the body.
Date posted: June 4, 2019. Answers (1)
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Define a free fall.
Date posted: June 4, 2019. Answers (1)
- The figure below shows a ray of light incident at an angle of 35.60 at point D on the first face of a glass prism...(Solved)
The figure below shows a ray of light incident at an angle of 35.60 at point D on the first face of a glass prism ABC. The refractive index of the prism is 1.6.
(i) Determine the angle of refraction at point D.
(ii) Find the angle of incidence of the refracted ray on the face AC to 1 decimal point.
(iii) Complete the ray diagram to show the emergent ray from the face AC.
(iv) State two conditions necessary for total internal reflection to occur.
Date posted: June 3, 2019. Answers (1)
- A heater is rated 2000W is used to heat water for 5 hours. Calculate the cost of electricity at Ksh.6.70 per unit.(Solved)
A heater is rated 2000W is used to heat water for 5 hours. Calculate the cost of electricity at Ksh.6.70 per unit.
Date posted: June 3, 2019. Answers (1)
- An object of height 10.5cm stands before a diverging lens of focal length 20cm and a distance of 10cm from the lens. Determine;
(i) image distance....(Solved)
An object of height 10.5cm stands before a diverging lens of focal length 20cm and a distance of 10cm from the lens. Determine;
(i) image distance.
(ii) height of the image.
(iii) magnification.
Date posted: June 3, 2019. Answers (1)
- The figure below shows an object in front of lens.
(i) Using rays locate the image as seen by observer, E.
(ii) Give one application of...(Solved)
The figure below shows an object in front of lens.
(i) Using rays locate the image as seen by observer, E.
(ii) Give one application of such a lens as used above.
(iii) Write three similarities between an eye and a camera.
Date posted: June 3, 2019. Answers (1)
- The work function of a clean metal surface is 7.5eV. Calculate.
(i) The minimum frequency of radiation that will cause the emission of electrons from the...(Solved)
The work function of a clean metal surface is 7.5eV. Calculate.
(i) The minimum frequency of radiation that will cause the emission of electrons from the surface. (Plank’s constant h = 6.63 x 10-34Js, electronic charge e = 1.6 x 10-19C).
(ii) The maximum energy of the electrons emitted when the surface is illuminated with a radiation of frequency 2.0 x 1015HZ.
Date posted: June 3, 2019. Answers (1)