Answer:
-833.3 N/C
Explanation:
Kinetic energy, K, in terms of electric field, E, is given as:
K = qEr
q = charge = e = 1.6 × 10⁻¹⁹C
E = Electric field
r = distance = 0.3m
The electric field can be gotten by making E subject of formula:
E = K/(qr)
The electeic field needed to stop the electrons must be equal in magnitude to the electric field carried by these electrons:
E = (4.0 × 10⁻¹⁷)/(-1.6 × 10⁻¹⁹ * 0.3)
E = -833.3 N/C
This is the electric field needed to stop the electrons.
The negative sign means that the electric field must be in a direction opposite to the motion of the electrons.
Answer:
B
Explanation:
Simply take all forces pointing to the right of the box as positive and all of the forces pointing to the left of the box as negative and add all values.
ΣF = 7 + 18 + (-20) = 5N to the right
Answer:
F = 39.2 N
Explanation:
Since, the object is in uniform motion. Therefore, the frictional force on object will be:
Frictional Force = μk N = μk mg
where,
μk = coefficient of kinetic friction = 0.2
m = mass of crate = 10 kg
g = 9.8 m/s²
Therefore,
Frictional Force = (0.2)(10 kg)(9.8 m/s²)
Frictional Force = 19.6 N
The horizontal component of force must be equal to this frictional force to continue the uniform motion:
F Sin 30° = 19.6 N
F = 19.6 N/Sin 30°
<u>F = 39.2 N</u>
Before you step on the brakes, the car has kinetic energy, when you step on the brakes, it turns the kinetic energy into heat (thermal energy). When it stops completely, it has potential energy. Hope this helped :)
Here in all such collision type question we can use momentum conservation as we can see that there is no external force on this system
as we know that
now from above equation we have
so the speed of combined system is 2 m/s
