Answer:

Explanation:
Given data
velocity v₀=20 cm/s at time t=3s
velocity vf=0 at time t=8 s
To find
Average Acceleration at time=3s to 8s
Solution
As we know that acceleration is first derivative of velocity with respect to time
Answer:
Number of electrons, 
Explanation:
Given that,
Charge on the fly, 
Let n is the number of electrons lose to the surface it is walking across. It is case of quantization of electric charge. It is given by :



n = 387500000 electrons
or

So, there are
electrons. Hence, this is the required solution.
This question is incomplete, the complete question is;
A block of mass m begins at rest at the top of a ramp at elevation h with whatever PE is associated with that height. The block slides down the ramp over a distance d until it reaches the bottom of the ramp.
How much of its original total energy (in J) survives as KE when it reaches the ground? m = 9.9 kg h = 4.9 m d = 5 m μ = 0.3 θ = 36.87°
Answer:
the amount of its original total energy (in J) that survives as KE when it reaches the ground will is 358.975 J
Explanation:
Given that;
m = 9.9 kg
h = 4.9 m
d = 5 m
μ = 0.3
θ = 36.87°
Now from conservation of energy, the energy is;
Et = mgh
we substitute
Et = 9.9 × 9.8 × 4.9
= 475.398 J
Also the loss of energy i
E_loss = (umg cosθ) d
we substitute
E_loss = 0.3 × 9.9 × 9.8 × cos36.87° × 5
= 116.423 J
so the amount of its original total energy (in J) that survives as KE when it reaches the ground will be
E = Et - E_loss
E = 475.398 J - 116.423 J
E = 358.975 J
Answer:
$ 18.75
Explanation:
given,
capacity of the Dave’s car = 12 gallons
Assuming that the tank is 3/8 full before
Cost of gas per gallon = $2.50 per gallon of gas
Volume Dave have to fill
=
=
of full tank
=
volume Dave have to fill = 7.5 gallons
total money Dave spent
= 7.5 gallons x $2.50
= $ 18.75
Dave have to spend $ 18.75 to fill tank to it capacity.