Answer:
Explanation:
This is one-dimensional motion on an incline which makes it so much more funner :/
The equation for this is
w*sinθ - f = ma which is just a fancy version of Newton's second law that says that the sum of the forces acting on an object are equal to that object's mass times its acceleration.
w is the weight of the teen which is also the normal force, [tex]F_n[/tex]. Therefore,
[tex]w=F_n=mg[/tex] where m is mass and g is gravity:
[tex]w=F_n=(74.2)(9.8)[/tex] and we need 2 sig figs for this since there are 2 in 9.8:
w = 730N
Since there is no friction in this problem, the value for f, frictional force, is 0, making our job a bit shorter. Filling in the main equation:
730sin38 - 0 = 74.2a
Since the left side is subtraction and we will eventually have to divide, and the rules for subtraction/addition are different from those for multiplication/division, we will have to subtract first, get the correct number of sig figs for that difference, and then divide, following the rules for division.
730sin38 will have 2 sig figs which is 450. Now
450 - 0 = 74.2a and
450 = 74.2a and divide to 2 sig figs:
a = 6.1 m/s/s
