The first one shows that it is going at a constant speed, the second shows them going faster, the last shows them slowing down.
If the acceleration is constant (negative or positive) the instantaneous acceleration cannot be
Average acceleration: [final velocity - initial velocity ] /Δ time
Instantaneous acceleration = d V / dt =slope of the velocity vs t graph
If acceleration is increasing, the slope of the curve at one moment will be higher than the average acceleration.
If acceleration is decreasing, the slope of the curve at one moment will be lower than the average acceleration.
If acceleration is constant, the acceleration at any moment is the same, then only at constant accelerations, the instantaneuos acceleration is the same than the average acceleration.
Constant zero acceleration is a particular case of constant acceleration, so at constant zero acceleration the instantaneous accelerations is the same than the average acceleration: zero. But, it is not true that only at zero acceleration the instantaneous acceleration is equal than the average acceleration.
That is why the only true option and the answer is the option D. only at constant accelerations.
Answer:
Because alkali metals are so reactive, they are found in nature only in combination with other elements. They often combine with group 17 elements, which are very “eager” to gain an electron.
Explanation:
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Speed of the Enemy sub .....> <span> 25.0 km/hr which is (25/3.6) m/s = 6.94 m/s
We use the expression Speed = Distance/ time to find the distance
D = Speed*Time = 6.94 m/s * 3.5 = 24.305 m
The enemy sub will be 24.305 m closer </span>
Answer: 
Explanation:
Given
mass of laptop m=2 kg
The velocity of car u=8 m/s
The coefficient of static friction is 
The coefficient of kinetic friction is 
As the car is moving, so the coefficient of kinetic friction comes into play
deceleration offered by friction 
Using the equation of motion 
insert the values
