Answer:
C) Use two batteries instead of one.
Explanation:
-Strength of an electromagnet depends on the electrical current which flows through the wires.
-Two batteries have a higher current than one and thus higher strength in the electromagnet.
Answer:
(B) the sum total of all matter and energy
Explanation:
Universe comprises of all the matter and energy that exists in space. It contains billions of stars, planets and interstellar matter that is clouds of dust and gas. There is large amount of the empty space in between.
Universe contains stars as many as grains of sand on all beaches on the Earth. These stars are grouped into galaxies. Milky Way is one of the galaxies. Galaxies can be grouped into clusters and super-clusters.
Answer:
v = 72 km / h
Explanation:
The definition of average speed is the distance traveled between the time interval
v = Δx / Δt
let's find the distance traveled
x = 60 + 30
x = 90 km
time spent, all time must be included, travel time and when stopped
t = 0.45 + 0.15 + 0.5+ 0.15
t = 1.25 h
we substitute in the initial equation
v = 90 / 1.25
v = 72 km / h
in going from one city to the other
The formulas are-
a=f/m
f=ma
m=f/a
