Answer:
Distance of 400m.
Explanation:
Use your kinematics equation to solve for distance (we can use kinematics b/c acceleration is constant).
d = (initial velocity x time) + 1/2 at^2
d = (20 x 10) + 1/2 (4) (10)^2
d = 200 + 200
d = 400 m
Answer:
The shortest distance in which you can stop the automobile by locking the brakes is 53.64 m
Explanation:
Given;
coefficient of kinetic friction, μ = 0.84
speed of the automobile, u = 29.0 m/s
To determine the the shortest distance in which you can stop an automobile by locking the brakes, we apply the following equation;
v² = u² + 2ax
where;
v is the final velocity
u is the initial velocity
a is the acceleration
x is the shortest distance
First we determine a;
From Newton's second law of motion
∑F = ma
F is the kinetic friction that opposes the motion of the car
-Fk = ma
but, -Fk = -μN
-μN = ma
-μmg = ma
-μg = a
- 0.8 x 9.8 = a
-7.84 m/s² = a
Now, substitute in the value of a in the equation above
v² = u² + 2ax
when the automobile stops, the final velocity, v = 0
0 = 29² + 2(-7.84)x
0 = 841 - 15.68x
15.68x = 841
x = 841 / 15.68
x = 53.64 m
Thus, the shortest distance in which you can stop the automobile by locking the brakes is 53.64 m
Wavespeed = frequency x wavelength
= 14 x 9
= 126 mm/s
= 0.126 m/s
The rule is always the same. Your final answer must have the same number of significant figures as the least accurate value in the calculation (one with the least number of significant figures) I hope this makes sense
