Given :
Mass of block , M = 20 kg .
Force applied , F = 80 N .
Acceleration of block ,
.
To Find :
The coefficient is Kinetic force friction between the block and the table .
Solution :
We know , Force equation on block is given by :

Therefore , coefficient is Kinetic force friction between the block and the table is 0.15 .
Hence , this is the required solution .
Answer:
(a) Number of electrons per second strike the target is 3.125 x 10¹⁵.
(b) Charge that strikes the target in 0.750 s is 3.75 x 10⁻⁴ C .
Explanation:
(a) Let n be the number of electrons per second strike the target. We know that current (I) is given by the relation :
I = n x e
Here e is charge of electron.
Substitute 0.500 x 10⁻³ A for I and 1.6 x 10⁻¹⁹ C for e in the above equation.
0.500 x 10⁻³ = n x 1.6 x 10⁻¹⁹
n = 3.125 x 10¹⁵
(b) Let q be the charge that strikes the target. We know that :
q = I x t
Here I is current and t is time.
Substitute 0.500 x 10⁻³ A for I and 0.750 s for t in the above equation,
q = 0.500 x 10⁻³ x 0.750
q = 3.75 x 10⁻⁴ C
Inertia is the tendency of an object to resist a change in its motion.
I think the answer is B 1:100