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R-Helium
Characteristics:
i) It is unreactive
ii) Does not conduct heat and electricity
Kavungya answered the question on May 31, 2019 at 06:47
- A ball is thrown vertically upwards from the ground. It rises up to the highest point and then returns to the ground.Taking
the upward velocity to...(Solved)
A ball is thrown vertically upwards from the ground. It rises up to the highest point and then returns to the ground.Taking
the upward velocity to be positive, sketch the velocity -time graph for the motion.
Date posted: May 31, 2019. Answers (1)
- The mass of the fabric of a large balloon is 100kg. The balloon is inflated with 200cm3 of helium. The balloon is attached to a...(Solved)
The mass of the fabric of a large balloon is 100kg. The balloon is inflated with 200cm3 of helium. The balloon is attached to a cable fixed to the ground as shown.
(Density of air and helium are 1.25kg/m3 and 0.2kg/m3 respectively)
i) Indicate all the forces acting on the system.
ii) If the system is at equilibrium, write an equation relating the three forces in (i) above.
iii) Calculate the upthrust on the balloon.
Date posted: May 31, 2019. Answers (1)
- Explain why most of the x-ray tube is surrounded by lead metal.(Solved)
Explain why most of the x-ray tube is surrounded by lead metal.
Date posted: May 31, 2019. Answers (1)
- Figure below shows circular waves approaching a plane barrier in uniform medium.
On the diagram sketch the reflected waves.(Solved)
Figure below shows circular waves approaching a plane barrier in uniform medium.
On the diagram sketch the reflected waves.
Date posted: May 31, 2019. Answers (1)
- A house has two 100w bulbs, two 60w bulbs and one 75w bulb. Determine the cost of having all the bulbs switched on for 60...(Solved)
A house has two 100w bulbs, two 60w bulbs and one 75w bulb. Determine the cost of having all the bulbs switched on for 60 hours, given that the cost of electricity is 50cents per kilowatt hour find the cost.
Date posted: May 31, 2019. Answers (1)
- Figure below shows an object placed in front of a convex mirror.
On the same diagram draw the appropriate rays and locate the image formed.(Solved)
Figure below shows an object placed in front of a convex mirror.
On the same diagram draw the appropriate rays and locate the image formed.
Date posted: May 31, 2019. Answers (1)
- Explain why objects float higher in salty water than in fresh water.(Solved)
Explain why objects float higher in salty water than in fresh water.
Date posted: May 31, 2019. Answers (1)
- A person of mass 50kg is on a swing which has a speed of 10m/s at the lowest point of its motion. The ropes of...(Solved)
A person of mass 50kg is on a swing which has a speed of 10m/s at the lowest point of its motion. The ropes of the swing
are 2.5m long, Find the tension of the ropes. (Take g = 10ms-2)
Date posted: May 31, 2019. Answers (1)
- A motorcycle is travelling at a constant speed of 72km/h around a circular track of radius 150m.
i) Determine its centripetal acceleration.
ii) How long does...(Solved)
A motorcycle is travelling at a constant speed of 72km/h around a circular track of radius 150m.
i) Determine its centripetal acceleration.
ii) How long does the cyclist take to complete one full cycle of the track?
Date posted: May 31, 2019. Answers (1)
- Figure below shows an incident ray normal to the surface BC of a right-angled glass prism ABC. The critical angle of the glass is 420
Complete...(Solved)
Figure below shows an incident ray normal to the surface BC of a right-angled glass prism ABC. The critical angle of the glass is 420
Complete the diagram to show the path of the ray.
Date posted: May 31, 2019. Answers (1)
- A current carrying conductor AB is in a magnetic field as shown in figure below.
a) Indicate the direction of the force F acting on the...(Solved)
A current carrying conductor AB is in a magnetic field as shown in figure below.
a) Indicate the direction of the force F acting on the conductor.
b) State two factors that determine the direction of the force F.
Date posted: May 31, 2019. Answers (1)
- State two factors on which the linear speed of a body moving in a circular motion depends.(Solved)
State two factors on which the linear speed of a body moving in a circular motion depends.
Date posted: May 31, 2019. Answers (1)
- A battery is rated 100AH. How long will it work if it steadily supplies a current of 2.5A(Solved)
A battery is rated 100AH. How long will it work if it steadily supplies a current of 2.5A
Date posted: May 31, 2019. Answers (1)
- A column of glycerine 8.20m high, a column of sea water 10.08m high, column of mercury 0.76m high and a column of fresh water 10.34m...(Solved)
A column of glycerine 8.20m high, a column of sea water 10.08m high, column of mercury 0.76m high and a column of fresh water 10.34m high exert the same pressure at the bottom of the container.Given that the pressure exerted by a fluid is given by P = h g, arrange these liquid in decreasing order of their densities.
Date posted: May 31, 2019. Answers (1)
- 5 images are formed when two mirrors are inclined at an angle between them. Determine the angle of inclination.(Solved)
5 images are formed when two mirrors are inclined at an angle between them. Determine the angle of inclination.
Date posted: May 31, 2019. Answers (1)
- The figure below shows a metal sphere of mass 2kg moving along a smooth horizontal surface PQ, with a steady speed of
4m/s.
a) Explain why the...(Solved)
The figure below shows a metal sphere of mass 2kg moving along a smooth horizontal surface PQ, with a steady speed of
4m/s.
a) Explain why the speed of the sphere decreases as it moves up along QR.
b) If the sphere reaches R with a speed of 1.0m/s, calculate the change in its K.E from Q to R.
Date posted: May 31, 2019. Answers (1)
- A stone of mass 450g is rotated in a vertical circle at 3 revolutions per second. If the string has a length of 1.5m,
determine:
(i) the...(Solved)
A stone of mass 450g is rotated in a vertical circle at 3 revolutions per second. If the string has a length of 1.5m,
determine:
(i) the linear velocity
(ii) The tension of the string at positions A and B.
Date posted: May 31, 2019. Answers (1)
- A mass of wax of 1kg was heated uniformly by a 100W heating element until it melted. The graph below shows how the temperature of...(Solved)
A mass of wax of 1kg was heated uniformly by a 100W heating element until it melted. The graph below shows how the temperature of the wax varies with time.
(i) Explain what is happening in the region.
AB
BC
(ii) Calculate the specific heat capacity of the wax.
(iii) Calculate the specific latent heat of fusion of wax.
Date posted: May 31, 2019. Answers (1)
- The figure below shows a model of a spray gun. When air is blown in the direction shown, a spray is observed. Explain this observation.(Solved)
The figure below shows a model of a spray gun. When air is blown in the direction shown, a spray is observed. Explain this observation.
Date posted: May 31, 2019. Answers (1)
- An external force applied to a ball of mass 160g increases its velocity from 25cm/s to 275cm/s in 10 seconds. Calculate the
force applied.(Solved)
An external force applied to a ball of mass 160g increases its velocity from 25cm/s to 275cm/s in 10 seconds. Calculate the
force applied.
Date posted: May 31, 2019. Answers (1)