It’s a snowy day and you’re pulling a friend along a level road on a sled. You’ve both been taking physics, so she asks what you think the coefficient of friction between the sled and the snow is. You’ve been walking at a steady m/s, and the rope pulls up on the sled at a angle. You estimate that the mass of the sled, with your friend on it, is kg and that you’re pulling with a force of N. What answer will you give?
The co-efficient of friction is
walking at a steady m/s
the rope pulls up on the sled at a angle
and with your friend on it, is kg and that you're pulling a force of N
the free body diagram, as shown above, with the pulling tension force of the rope acting at a angle with the horizontal on the sled, the friction , weigh and normal reaction
we can express the coefficient of friction as
An object of mass m is at rest at the top of a smooth slope of height and length . The coefficient of kinetic friction between the object and the surface, , is small enough that the object will slide down the slope after being given a very small push to get it started. Find an expression for the object’s speed at the bottom of the slope.
A person with compromised pinch strength in his fingers can exert a force of only to either side of a pinched object, such as the book shown in FIGURE . What is the heaviest book he can hold vertically before it slips out of his fingers? The coefficient of static friction between his fingers and the book cover is .
A block of mass is at rest at the origin at . It is pushed with constant force from to across a horizontal surface whose coefficient of kinetic friction is . That is, the coefficient of friction decreases from at to zero at .
a. Use what you've learned in calculus to prove that
b. Find an expression for the block's speed as it reaches position .
A stubborn, 120 kg mule sits down and refuses to move. To drag the mule to the barn, the exasperated farmer ties a rope around the mule and pulls with his maximum force of 800 N. The coefficients of friction between the mule and the ground are ms = 0.8 and mk = 0.5. Is the farmer able to move the mule?
94% of StudySmarter users get better grades.Sign up for free