Answer:
The car's average speed is 16 feet per second.
Explanation:
The expression for the average speed is as follows;
Given expression of distance:
Put t= 4 s.
d(4)= 36 ft
Put t= 7 s in the given expression.
d(7)= 84 ft
Calculate the car's average speed over the interval of time from t = 4 seconds to t = 7 seconds.
A.S= 16 feet per second
Therefore, the car's average speed is 16 feet per second.
Capacitance C of a parallel plate capacitor is C=Q/V, where Q is the charge on the plates and V is the potential difference between the plates. The potential of the capacitor is then: V=Q/C.
The capacitance C is given by the equation C=k*ε₀*(A/d) where k is the dielectric constant, ε₀ is the permittivity of free space, A is the surface of the plate and d is the distance between the plates.
For vacuum and air, k=1 so the capacitance is C=ε₀*(A/d).
But when we insert a dielectric between the plates like teflon which has k=2.1 at T=20°C the capacitance becomes:
C₁=k*ε₀*(A/d)=2.1*ε₀*(A/d)=2.1*C.
We can see that the capacitance increases by k=2.1 which is the dielectric constant of teflon.
So the voltage V becomes:
V₁=Q/C₁=Q/(2.1*C)=(1/2.1)*(Q/C)=(1/2.1)*V=0.48*V.
V₁=0.48*V.
Potential difference decreases by 0.48 because we inserted teflon between the plates.
Answer:
Some of the kinetic energy from B has been transferred to A
Explanation:
In elastic collision, kinetic energy is conserved. Since A had 0 kinetic energy before the collision, while B has some kinetic energy. And kinetic energy is defined as
As the speed of B decreases post-collision, and its mass stays the same, kinetic energy of B must have been decreased as well.
A gains speed post collision, and so does its kinetic energy. So according to the law of energy conservation, some kinetic energy from B must have been transferred to A.
Answer:
75.5degrees
Explanation:
Magnitude of magnetic flux= BA
If rotated through an angle= BAcos theta
= (0.25)BA=BAcos theta
= costheta= 0.25
= theta= cos^-1 0.25
=75.5degrees
Before 7 after 9. A pH smaller than 7 indicates acidity with 0 being completely acidic. A pH greater than 7 shows alkalinity with 14 being completely alkaline. 7 is neutral. Since NaOH is alkaline, adding it to a neutral substance would increase the pH and it would increase from 7 to 9.