Question

A 70 kg climber is ascending a rockface that is inclined at an angle of 60◦ above the horizontal.

(a) At one point, the climber is unable to find a toehold for their left foot, and has to rely on the friction between the rockface and their shoe to support themselves while they plan their next move. You can assume that their weight is evenly distributed between their two feet.

i) What is the frictional force between their left shoe and the rockface?

ii) What is the minimum coefficient of static friction required for the climber to be able to support themselves in this manner?

(b) Later in the ascent, the climber reaches a section of the rockface that is vertical. As a safety measure, they create and attach an anchor to the rockface that is capable of supporting their weight if their feet slip. The anchor consists of a rope attached to two points on the rockface with a clip in the middle of rope that is attached to the climber. When the climber hangs from the anchor, the rope on either side of the clip makes an angle of 40◦ with the vertical. What is the magnitude of the tension in the rope at this time?

Answer 1