Answer:
c
Explanation:
The changing of color of a substance is not necessarily an indicator of a chemical change. For example, changing the color of a metal does not change its physical properties. However, in a chemical reaction, a color change is usually an indicator that a reaction is occurring.
Answer:
W = 30.38 N
Explanation:
Given that,
Mass of a rock, m = 3.1 kg
We need to find the weight of the rock on the surface of Earth. Weight of an object is given by :
W = mg
g is the acceleration due to gravity, g = 9.8 m/s²
W = 3.1 kg × 9.8 m/s²
= 30.38 N
So, the weight of the rock on the Earth is 30.38 N.
Very high-energy objects and events spit out very high-energy photons, so the instrument you need in order to detect them is the X-ray telescope. <em>(C) </em>
Inconveniently, X-ray telescopes only work when they're up in orbit, because X-rays get seriously soaked up in Earth's atmosphere, and most of them never make it down to the surface ... (lucky for us !) .
Answer:
a= 17.69 m/s^2
Explanation:
Step one:
given data
A car accelerates uniformly from rest to 23 m/s
u= 0m/s
v= 23m/s
distance= 30m
Step two:
We know that
acceleration= velocity/time
also,
velocity= distance/time
23= 30/t
t= 30/23
t= 1.30 seconds
hence
acceleration= 23/1.30
accelaration= 17.69 m/s^2
