PLEASE SHOW FULL STEPS: problem 1 : Problem 1 A) To loosen a stubborn bolt it he

Question

PLEASE SHOW FULL STEPS:

problem 1 :

Problem 1

A) To loosen a stubborn bolt it helps to use a longer rather than a shorter wrench. Why?

B) To loosen a stubborn screw, is it better to use a screwdriver with a long thin handle or a screw driver with a short fat

handle. Justify your answer.

problem 2 :

Consider a merry-go-round in the shape of a uniform disc of mass 400 kg and radius 3 m. Two children each of

mass 20 kg sit on the edge of the merry-go-round. A person pushes on the edge of the merry-go-round at an angle of 70 degree

to the radial direction (20 degree with respect to the tangential direction.). What is the magnitude of the constant force that this must

person apply to accelerate the merry-go-round from rest to an angular speed of 0.8 rad/s in a time of 2.5 seconds?

Explanation / Answer

1) A) longer , Torque = F*lever arm . so for larger wrench levr armwill be large

B) short far


2) I = (1/2)M*R^2 + 2*m*R^2 = (1/2)*400*3^2 + 2*20*3^2
I = 2160 kg m^2

alfa = W/t = 0.8/2.5 = 0.32 ra/s

Torque = F*R*sin70 = I*alfa = 691.2


F = 691.2/(3*sin70) = 245.18655878 N


3)

A)m1*g - T = m1*a

T- m2*g = m2*a

a = (m1-m2)*g/(m1+m2) = (4-3)*9.8/(4+3) = 1.4 m/s^2

B)
I = (1/2)M*R^2

net Torque = I*alfa

T1*R - T2*R = I*alfa

(T1-T2)*R = (1/2)*M*R^2*a/R

(T1 -T2)*R^2 = (1/2)*M*a

T1 - T2 = a..........(1)

along vertical

m1*g - T1 = m1*a.........(2)

T2 - m2*g = m2*a...........(3)

2+3 gives


T2 - T1 + m1*g - m2*g = (m1+m2)*a.........(4)

substituting 1 in 4

-a + (4-3)*9.8 = (4+3)*a


a = 1.225 m/s^2

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