1. D
2. A
I’m not sure on 3
Answer:
Reduce you're speed, and let the other vehicle pass you
The lens equation gives d relation between focal length, object distance n image distance.
1/f = 1/v + 1/u
seldon
You need to know how much friction that object.
Answer:
Explanation:
To solve this problem we use the Hooke's Law:
(1)
F is the Force needed to expand or compress the spring by a distance Δx.
The spring stretches 0.2cm per Newton, in other words:
1N=k*0.2cm ⇒ k=1N/0.2cm=5N/cm
The force applied is due to the weight

We replace in (1):
We solve the equation for m: