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Phy 050:Physics Question Paper

Phy 050:Physics

Course:Education

Institution: Kenya Methodist University question papers

Exam Year:2011

END OF SECOND TRIMESTER 2011 EXAMINATIONS

FACULTY : EDUCATION & SOCIAL SCIENCES
DEPARTMENT : EDUCATION AND PRE-UNIVERSITY
COURSE CODE : PHY 050
COURSE TITLE : Physics
TIME : 2 HOURS
INSTRUCTIONS
• Answer Question ANY THREE Questions
• CONSTANTS:
Acceleration due to gravity (g) = 10m/s2
Universal gravitational constant (G) = 6.67 x 10-11 Nm2/kg2
Question 1
a) i) Explain the difference between a scalar quantity and a vector quantity. (2marks)
ii) Give THREE examples of a scalar quantity and THREE examples of a vector
quantity. (3marks)

b) A ball is thrown vertically upwards from the ground with a velocity of 20mls. Calculate:
i) The maximum height reached.
ii) The time taken to reach the maximum height.
iii) The time taken to reach the ground again after the ball is thrown up.
iv) The velocity reached half-way to the maximum height. (12marks)

c) A car travels at a uniform velocity of 20m/s for 5 seconds. The brakes are then applied and the car comes to rest with uniform retardation in a further 8 seconds. Draw a sketch graph of the velocity against time for the motion. (3marks)

Question 2
a) i) State Newton`s laws of motion. (3marks)
ii) State the law of conservation of momentum. (2marks)

iii) Using the equation of the rate of change of momentum i.e.
Rate of change of momentum = mv - mu
t
where Mv = Final momentum
Mu = Initial momentum
t = time taken.
Show that Newton`s second law is give by:
F= Constant x Ma where F = force
M = Mass and
a = Acceleration. (5marks)

b) A bullet of mass 0.006kg travelling at 120m/s penetrates deeply into a fixed target, and is brought to rest in 0.01 seconds. Calculate:
i) The distance of penetration of the target. (4marks)
ii) The average retarding force exerted on the bullet. (2marks)

c) A resultant force of 12N acts for 5 seconds on a mass of 2kg.
i) What is the change in momentum of the mass?
ii) What would be the change in momentum of a mass of 10kg under the same
conditions. (4marks)

Question 3
a) i) State the Ohm`s law (2marks)
ii) Using well labeled diagrams, draw resistors
in series
in parallel (6marks)

b) A battery C of 2.2 V and negligible internal resistance, is connected to the combination of
resistors shown below: 10p
I1 10p D I3
A E
I2
C
5p 5p

B G F

What are the values of the currents I1, I 2 and I3 (8marks)

c) Briefly define the following terms:
i) Resistance
ii) Resistivity (4marks)

Question 4
a) Briefly explain the meaning of the following terms as used in physics.
i) Work
ii) Power (4marks)

b) i) A car of mass 1000kg moving on a horizontal road with a steady velocity of
10m/s has a total frictional force on it of 400N. Find the power due to the engine.
(4marks)

ii) The car in (i) above now climbs, a hill at an angle of 8° to the horizontal,
Assuming the frictional force stays constant at 400N, what engine power is now needed to keep the car moving at 10m/s.? (6marks)

c) Differentiate between kinetic energy and potential energy. (4marks)

d) Determine the kinetic energy of a car of mass 1000kg moving with a velocity of 36km/hr.
(2marks)
Question 5
a) i) Define the term “electromotive force (emf) of a cell.” (2marks)

ii) A bulb rated 120v/90 watts is operated from a 120v power source. Find the current flowing through it and its resistance. (4marks)

b) Calculate the resistance of a wire 20m long that has a radius of 20mm and resistivity of 5.5x10-8 pm. If the two ends of the wire are connected to a source of 24v, what is the value of the of the current I? (7marks)

c)

r

L

R
I

Consider the circuit shown above which consists of source emf E with internal resistance
r = 0.1p with electric appliance L with resistance R which operates at 300 w. The voltage v is 110v while the current through the circuit is 5A.
Calculate:
i) The power output from the source
ii) The power used in joule heating of R.
iii) The magnitude R.
iv) The power in source itself
v) The e.m.f of the source (7marks)

Phy 050:Physics Question Paper

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