Answer:
<em>a. The cart's acceleration is 2 m/s^2</em>
<em>b. The cart will travel 100 m</em>
<em>c. The speed is 20 m/s</em>
Explanation:
a. The acceleration of the cart can be calculated using Newton's second law:
F = m.a
Solving for a:

The cart has a mass of m=15 Kg and is applied a net force of F=30 N, thus:


b.
Now we use kinematics to find the distance and speed:

The cart starts from rest (vo=0). The distance traveled in t=10 seconds is:


The cart will travel 100 m
c.
The final speed is calculated by:

The speed is 20 m/s
A because the dot nearst to a
Answer:
Option D is the correct answer.
Explanation:
We equation for elongation
Here we need to find weight required,
We need to stretch a steel road by 2 mm, that is ΔL = 2mm = 0.002 m

E = 200GPa = 2 x 10¹¹ N/m²
L=2m
Substituting

Option D is the correct answer.
Let's say the distance is D. Then the time going is D/10 sec. The time returning is D/20 s. The total time is 3D/20 s, and the total distance is 2D. The average speed for the round trip is (total distance)/(total time). That's (2D) ÷ (3D/20). That's (40D/3D) which is 13-1/3 m/s. (I thought it was going to depend on the distance, but it doesn't.)