Answer to Question #71115 in Mechanics | Relativity for John Citty

Question

A car starts from rest and rolls down a hill. The height of the hill is .3 km and the distance travelled by the car is 4.8 km. What is the acceleration?

Answer 1

"h\=" 3"km"
"l\=" 4"\." 8"km"
"g\=\1\0" 〖"ms" 〗^(-2)
a-?
The force that accelerates the car is "F\=mgsin\α" , where "sin\α\=" h/l
Second Newton's Law gives
"mgsin\α\=ma" ,
Thus, we obtain
"a\=gsin\α\=\1\0"⋅3/(4"\."8)=6"\.\2\5" 〖"ms" 〗^(-2)

Answer: "a\=" 6"\.\2\5" 〖"ms" 〗^(-2)