table is lifted to backpack starts to slide off. If table makes a 21 degree angle with floor, what is coefficient of static friction between backpack and the table?

(mu_s)*M*g cos 21 = M*g*sin 21

mu_s = sin21/cos21 = tan21 = 0.384
is the static coefficient of friction

To find the coefficient of static friction between the backpack and the table, we can use the equation:

μs = tan(θ)

where μs is the coefficient of static friction and θ is the angle the table makes with the floor.

In this case, the given angle θ = 21 degrees. So, we can substitute this value into the equation to find the coefficient of static friction.

μs = tan(21°)

To simplify this, let's use a scientific calculator or an online calculator to evaluate the tangent of 21 degrees.

Using a calculator, tan(21°) is approximately 0.3894.

Therefore, the coefficient of static friction between the backpack and the table is approximately 0.3894.