Question

A string can bear a maximum tension of 490N. The maximum number of rotations per second it can make in a
horizontal circle of radius 1m when 500gm is attached at its end is
75
1140
4r
14
1) V3
4) 7.55
47
TC​

Answer 1

Answer:

@14yrs

Explanation:

maximum tension is present at down because  when body is down

only tension acts upward and weight,centripetal force acts upwards

when body is up tension,weight acts down and  centripetal force upward

t=mg+mv^2/r

490=5+0.5*v^2/1

490=5+0.5v^2

485=0.5v^2

970=v^2

v=31.14

v=rw

31.14=w

del theta= omega*t+1/2at^2

del theta=omega*t+1/2at^2

del theta=31.14*t+1/2(mv^2/r)*t^2

del theta=31.14*t+1/2(0.5*970)*t^2

del theta=31.14+242.5=273.64

here del theta is in meters by dividing by 2pi it gets converted into rotations

therefore max rotations=273.64/6.28

=43.57~44 rotations