The distance you traveled is 18.36 m which is less than 50 m, so you will stop before you hit the tree.
How to calculate the distance traveled before stopping?
The distance traveled before stopping is calculated by applying the following kinematic equation as follows;
The coefficient friction on a dry road, μ = 0.9
The acceleration of the car is calculated as;
a = μg
a = 0.9 x 9.8 m/s²
a = 8.82 m/s²
The distance you traveled before stopping is calculated as;
v² = u² - 2as
where
- v is the final velocity
- u is the initial velocity
- s is the distance traveled
when you stop, the final velocity = 0
0 = u² - 2as
s = u² / 2a
s = ( 18² ) / ( 2 x 8.82)
s = 18.36 m
Thus, the distance you traveled is 18.36 m which is less than 50 m, so you will stop before you hit the tree.
The complete question is below:
You are alertly driving a car at 20 mph (18 m/s). You come around a bend and see a tree that has fallen across the road 50 m away. Will you be able to stop before you hit the tree. (assume you are driving on a dry road).