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When the cold junction of a thermocouple thermometer is at 0oC and the hot junction at 100
oC, the millivoltmeter shows a deflection of 4.2 mV towards the left. The cold junction is now
put in an unknown temperature while maintaining the hot junction at 100oC. The
millivoltmeter now shows a deflection of 5.2 mV towards the right. Calculate the unknown
temperature
An endless belt 4 m long passes over a pulley of 300 mm diameter making 80 rev/minute. The pulley accelerates to 240 rev/minute in 40 seconds. If there is no belt slip, calculate:
7.1 the angular acceleration of the pulley and the linear acceleration of the belt.
7.2 the number of revolutions made by the pulley during its acceleration.
7.3 the number of times a point on the belt will pass over the pulley in 12 seconds.
Also clearly show the values of the following:
ω1
ω2
α
a
θ
ω2
θ
s
times
A 320 mm diameter-grinding wheel must be driven at a peripheral grinding speed of 1200 meters/min. It takes 62 seconds to reach this speed from rest, runs at this speed for the following two and a half minutes and then begins to decelerate uniformly, coming to rest after a further 10 seconds. Draw a neat angular velocity/time graph and use it to determine how many revolutions the wheel made since starting from rest.
Also clearly show what the following values are
v
ω
θ1
θ2
θ3
θtotal
1.1 The speed of a shaft increases from 93 r/min to 305 r/min with an angular acceleration of 2,4 rad/s2. How many revolutions does the shaft make during the first 3 seconds of acceleration? How many revolutions does the shaft make in the last 4.25seconds. Show all calculations[10]
1.2 A motor that runs at 1240 rev/minute is required to drive a belt at 20 m/s. What diameter belt pulley is required?[3]
Also clearly show the following values:
ωi
ωf
θ
r
d
ωf
A 350 mm diameter grinding wheel must be driven at a grinding speed (speed at circumference) if 1200 meters per minute. It takes 5 seconds to reach this speed from rest, runs at this speed for the next two minutes and then starts to decelerate uniformly, finally coming to rest after a further 30 seconds. Draw a neat angular velocity-time graph and determine how many revolutions the wheel made in total.
Also clearly show what the following values are:
ω1
θ1
θ2
θ3
θtotal
A pulley (A) diameter 300mm is accelerated by means of a belt drive from 60rpm to 240rpm during 360 revolutions. Attached by means of a belt is another pulley (B), with diameter 200mm. Calculate:
a)The angular acceleration of each pulley
b)The initial and final velocity of the smaller pulley (B) in rad/s
Also
Clearly show the values of the following:
Pulley A-ωi
Pulley A-ωf
Pulley A-αA
Pulley B-αB
Pulley B-ωi
Pulley B-ωf
A jet fighter aircraft is climbing vertically ay 120m/s when it releases a bomb that hits the ground 35seconds later. How high was the jet when the bomb was released?
A hovercraft stays off the ground by blowing air out underneath it. It can accelerate (forwards or backwards) at 0,6 m/s2 by blowing air with a steering fan (backwards or forwards). If the hovercraft is moving forwards at 12 m/s and the steering fan is suddenly turned to accelerate the hovercraft backwards, calculate:
a) the velocity of the hovercraft after 2 s
b) the time it takes for the hovercraft to reach zero velocity
c) the velocity of the hovercraft after 29 s
d) the displacement of the craft when it has zero velocity
e) the displacement of the hovercraft when it is moving backwards at 16m/s
f) Clearly show what the value of h(max),t(total) and v
State whether the hovercraft is going backwards or forwards after each question’s answer.
(Make forward direction positive and backwards direction negative)
1. Eight kilometers below the surface of the ocean the pressure is 82Mpa. Determine the density of the seawater at this depth if the density at the surface is 1025kg/m3 and the average bulk modulus of elasticity is 2.3GPa.
