Question

1. Describe the difference between static friction and kinetic friction. 2. You have a 1.20 kg cart resting on various surfaces. For each of the following scenarios, find the normal force acting on the cart (in standard units): a. The cart on a horizontal floor b. The cart carrying a load of 750 g on a horizontal floor c. The cart on an incline raised 15° above the horizontal d. The cart on a horizontal floor with a string attached to it that is pulling with a force of 10.0 N at an angle of 30° above the horizontal

Answer 1

Soln it Kinetic friction, lk Is Difference between static and Kinetic friction is the retarding force between two objects in contact that are moving against each other Kinetic frictional equals to b = M, N N is Normal between surfaces where Coe Coefficient of Kinetic friction is less than the coefficient of static friction for (us) same Contact lls > ulk static friction is the force that has to be overcome in order to get something fs to more A llls N

The force to induce motion is bigger than necessary to continue motion. the one so, ls > luk. (2) Given that, mass of cart 1. 20kg AM (a) N= т 9 mg = 0.20 (9.8) N=11.76 Newton (b) m m = 750g = 0.75 kg m m = 1.20 kg a system (mitm) g Taking mitm) as N = mitm) g 0.75 +1-2) 9.8 N = 19.11 Newton

(C) FBD ofm m 15° m ing cosis mgsin 15 mg N = mg cos 15° = (1.2) (9.8) (0-9) N = 11.28 Newton Tosin 30' (d) ON N. lo cos 3o mg As the box is in equilibrium, Nt 10 sin 30 = mg No (1.2) 9.8 – 10 XL 2 n 6.76 Newton