A mechanic’s torque wrench has a handle

PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

A mechanic’s torque wrench has a

0.30\,\text{m}

handle. To tighten a car wheel lug nut, the specification calls for a torque of

75\,\text{lb}\cdot\text{ft}

(pound-feet). The mechanic can pull only at a

60^{\circ}

angle relative to the handle because of limited clearance. (a) Convert the specified torque of

75\,\text{lb}\cdot\text{ft}

to newton-metres. (Use

1\,\text{lb}=4.45\,\text{N}

and

1\,\text{ft}=0.305\,\text{m}

.) (b) Determine the magnitude of the force the mechanic must apply to the handle at the given angle in order to meet the specified torque.