Aman is pulling a 13-kg sled across a flat, snowy surface. he holds the handle of the sled at a 30° angle with the ground.
what is the minimum pulling force (f) to the nearest newton that the man must exert to keep the sled moving? (use the following constants: coefficient of sliding friction = 0.15; acceleration due to gravity = 9.8 m/s2, cos 30 = 0.87.)

a. 9.5 nb. 20 nc. 19 nd. 22 ne. 130 n

A3.9 g aluminum foil ball with a charge of +4.1×10−9 c is suspended on a string in a uniform horizontal e⃗ field. the string deviates to the right and makes an angle of 30∘ with the vertical. part a part complete what information about the e⃗ field can you determine for this situation? what information about the field can you determine for this situation? only the magnitude of e⃗ only the direction of e⃗ both the magnitude and the direction of e⃗ none of the above previous answers correct part b determine the magnitude of the electric field. express your answer with the appropriate units. e e = nothing nothing request answer part c determine the direction of the electric field. determine the direction of the electric field. to the right to the left away from you toward you

Which of these has some mechanical energy? a. an atom b. heat inside earth c. a book on a shelf d. the fire from a lit match

You add 800 ml of water at 20c to 800 ml of water at 80c what is the most likely final temperature of the mixture ? a. 100c b. 60c c. 25 c d.50c