Answer:
0.88 cm
Explanation:
Initial length at 10°c, L = 23 m
Rise of temperature, Δt = 42 - 10 = 32°c
Coefficient of linear expansion of concrete, α = 12 x 10^(-6) per°c
Minimum spacing to be left = α L Δt
= 8.832 x 10^{-1} cm
= 0.88 cm
Note: I have a chosen a general value of 12 x 10^-6 per deg c for coefficient of expansion of concrete. However, please refer to the value given in your text book and substitute it for an accurate answer.
There are mistakes in the question.The correct question is here
A 2.0 kg, 20-cm-diameter turntable rotates at 100 rpm on frictionless bearings. Two 500 g blocks fall from above, hit the turntable simultaneously at opposite ends of a diameter, and stick. What is the turntable’s angular velocity, in rpm, just after this event?
Answer:
w=50 rpm
Explanation:
Given data
The mass turntable M=2kg
Diameter of the turntable d=20 cm=0.2 m
Angular velocity ω=100 rpm= 100×(2π/60) =10.47 rad/s
Two blocks Mass m=500 g=0.5 kg
To find
Turntable angular velocity
Solution
We can find the angular velocity of the turntable as follow
Lets consider turntable to be disk shape and the blocks to be small as compared to turntable
where I is moment of inertia