Abridge, constructed of 11 beams of equal length and negligible mass, supports an object of mass as shown. real bridges of this sort have steel rockers at the ends, these assure that the support forces on the bridge are vertical even when it expands or contracts thermally.

find f_p, the vertical force that pier p exerts on the left end of the bridge.

The vertical force that pier P exerts on the left end of the bridge,

Fp = ²/₃ Mg

The vertical force that pier Q exerts on the right end of the bridge,

Fq = ¹/₃ Mg

Let's recall Moment of Force as follows:

where:

τ = moment of force ( Nm )

F = magnitude of force ( N )

d = perpendicular distance between force and pivot ( m )

Let us now tackle the problem !

Given:

mass of the object = M

gravitational acceleration = g

Asked:

vertical force at pier P = Fp = ?

vertical force at pier Q = Fq = ?

Solution:

If the bridge is in equilibrium position , then :

Grade: High School

Subject: Physics

Chapter: Moment of Force

answer: b.

explanation:

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it