Answer:
f = 692 N
Explanation:
given data:
f =800N
a =1.2 m s^{2}
m= 90 kg
from newton's second law
net force 
therefore we have from above equation
ma =F - f
putting all value to get force of friction
1.2*90 = 800 - f
f = 692 N
Answer: The electric field is: a) r<a , E0=; b) a<r<b E=ρ (r-a)/εo;
c) r>b E=ρ b (b-a)/r*εo
Explanation: In order to solve this problem we have to use the Gaussian law in diffrengios regions.
As we know,
∫E.dr= Qinside/εo
For r<a --->Qinside=0 then E=0
for a<r<b er have
E*2π*r*L= Q inside/εo in this case Qinside= ρ.Vol=ρ*2*π*r*(r-a)*L
E*2π*r*L =ρ*2*π*r* (r-a)*L/εo
E=ρ*(r-a)/εo
Finally for r>b
E*2π*r*L =ρ*2*π*b* (b-a)*L/εo
E=ρ*b* (b-a)*/r*εo
Answer:
1) move away from the windows.
When abrupt changes in pressure (produced by the hurricane) affect the windows, they can "explode" and be a serious danger for the people.
2) Go to the lowest level of the building.
Is safer than the upper levels because the lower levels suffer less from the strength of the hurricane (being closer to the ground increases the structural resistance), make sure that you have everything you may need in case of an emergency.
Time t = ?
<span>When wave is moving from
y = 0 to y =12 cm</span>
By using the formula,
y = 15cos [(π/12) t)] =
0,
cos [(π/12) t)] = 0 =
cos (π/2), so,
(π/12)t = π/2,
t = (π/2) (12/π)
t = 12/2
<span>t = 6 sec</span>
<span>so 6 sec is the least amount of time required</span>
Answer: hello your question lacks the required diagram attached below is the required diagram
answer : Both cars will move backwards and stop due to friction.
Explanation:
Given that both cars are negatively charged, When the wedges are removed both cars will move backwards ( repelling each other ) because they are like poles, and Like poles repel each other. while unlike poles attract each other ( forward movement ) .
The cars will later come to a stop due to frictional forces between the cars and the surface.
