Answer:
The electric force between them if the pieces of grain are 2 cm apart is 
.
Explanation:
Given:
Charge on one grain, 
Charge on another grain, 
Separation between them, 
Electric force acting between two charges 
separated by a distance 
is given as:
Where, 
is Coulomb's constant equal to 
.
Now, plug in all the values and solve for 
.
Therefore, the electric force between them if the pieces of grain are 2 cm apart is .
Some say one year and a half
We have that the momentum p is given by the formula p=mv where m is the mass and v is the velocity. Since for A p=-14kgm/s and m=7, we have that the velocity is -14/7=-2m/s. Hence its speed is 2 m/s.
For b we have that p=15kgm/s and v=3m/s. Because m=p/v, we have m=3kg.
We also have that the momentum is conserved in this system. Hence, the net sum of the momentum of the 2 snowballs equals the momentum of the single giant ball. Hence, p(total)=p(combined)=-14+15=1kgm/s (momentum is a vector; the positive sign means that it tends to the positive direction).
Answer:
A
Since the car is moving to the right, the Normal Force is balancing the Weight and the Net Force is 10 N, right.
Explanation:
as the answers says, the only two forces in the y axis are the normal force and the weight, and they balance each other. On the x axis, you have 20N to the right and the friction is a force that opposes the movement, so the 10N are to the left. The net force is 20 - 10 = 10N.
Answer:
p2 = 9.8×10^4 Pa
Explanation:
Total pressure is constant and PT = P = 1/2×ρ×v^2
So p1 + 1/2×ρ×(v1)^2 = p2 + 1/2×ρ×(v2)^2
from continuity we have ρ×A1×v1 = ρ×A2×v2
v2 = v1×A1/A2
and
r2 = 2×r1
then:
A2 = 4×A1
so,
v2 = (v1)/4
then:
p2 = p1 + 1/2×ρ×(v1)^2 - 1/2×ρ×(v2)^2 = p1 + 1/2×ρ×(v1)^2 - 1/2×ρ×(v1/4)^2
p2 = 3.0×10^4 Pa + 1/2×(1000 kg/m^3)×(12m/s)^2 - 1/2×(1000kg/m^3)×(12^2/16)
= 9.75×10^4 Pa
= 9.8×10^4 Pa
Therefore, the pressure in the wider section is 9.8×10^4 Pa
