A physical change in something doesn't change what the it is. For example, if you break glass, it will still be glass. In a chemical change where there is a chemical reaction, a new thing is formed and energy is either given off or absorbed. For example, when you burn a log. The carbon in the log is reacting to the oxygen to create ashe and smoke
In 2Cr2O7 there’s 2 items; Cr and O
Answer:
a. 3 s.
Explanation:
Given;
angular acceleration of the wheel, α = 4 rad/s²
time of wheel rotation, t = 4 s
angle of rotation, θ = 80 radians
Apply the kinematic equation below,

Given initial angular velocity, ω₀ = 0
Apply the kinematic equation below;

Therefore, the wheel had been in motion for 3 seconds.
a. 3 s.
Answer:The voltage V in volts (V) is equal to the current I in amps (A) times the resistance R in ohms (Ω): V (V) = I (A) × R (Ω) The power P in watts (W) is equal to the voltage V in volts (V) times the current I in amps (A): P (W) = V (V) × I (A) AC Ohm's law calculator.
Explanation:
A proton has a positive (1+) charge