Explanation :
It is given that, the driver accelerates from a stop sign, cruises for 20 s at a constant speed of 60 km/h, and then brakes to come to a stop 40 s after leaving the stop sign.
We know that acceleration is defined as the rate of change of velocity.

Where
dv is the change in velocity, dv = 0 - 60 m/s = -60 m/s
dt is the change in time, dt = 40 s - 30 s = 10 s
So, 

From the graph it is clear that, from 30 s to 40 s the car is decelerating. So, at every second within this time the value of acceleration will be same i.e.
.
Answer:
The current drawn by the motor from the line is 4.68 A.
Explanation:
Given that,
Internal resistance of the dc motor, r = 3.2 ohms
Voltage, V = 120 V
Emf in the motor, 
We need to find the current drawn by the motor from the line. A dc motor with its rotor and field coils connected in series, applying loop rule we get :

I is current drawn by the motor

So, the current drawn by the motor from the line is 4.68 A. Hence, this is the required solution.
Answer:
See explanation
Explanation:
Favourite scientific discipline; Chemistry
Definition: Chemistry is the study of the composition, properties and uses of matter as well as the principles governing the changes that matter undergoes.
Source: New School Chemistry by Osei Yaw Ababio (2013)
Least Favourite Scientific Discipline: Botany
Definition: Botany is the study of plants, it includes the study of the structure and properties of plants, as well as the biochemical processes that go on in plants. It also involves the study of plant classification, plant diseases and interactions of plants with their environment.
Source: Encyclopedia Britiannica.
Answer:
B
Explanation:
this is because the neutrons do not have a charge, the things that have charge in an atom are electrons and protons.
and in the nucleus of an atom, there are protons and neutrons so you can see that A is not the answer
if you see the periodic table, you will know that the number of electrons and protons are equal, so the charges cancel each other out, hence the charge of an atom will be neutral
let me give you a tip which I got from my teacher, never write there is no charge in the atom, this suggests that there is no protons or electrons.
instead, write, the it is neutral
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