Answer:
The height is 0.1014 m
Explanation:
Given that,
Mass = 0.0400 g
Charge 
Time t = 0.0420 s
Electric field 
We need to calculate the electric force on the particle
Using formula of electric force

Put the value into the formula


We need to calculate the gravitational force
Using formula of force

Put the value into the formula


We need to calculate the net force



We need to calculate the acceleration
Using newton's law




We need to calculate the height
Using equation of motion



Hence, The height is 0.1014 m
Answer:
(A) She needs to move the decimal point by 3 places
Explanation :
It is given that,
Mass of the car, m = 1000 kg
Force applied by the motor, 
The static and dynamic friction coefficient is, 
Let a is the acceleration of the car. Since, the car is in motion, the coefficient of sliding friction can be used. At equilibrium,




So, the acceleration of the car is
. Hence, this is the required solution.
Answer:
n = 1.4
Explanation:
Given,
R1 = 18 cm, R2 = -18 cm
From lens makers formula
1/f = (n - 1)(1/18 + 1/18) = (n-1)/9
f = 9/(n-1)
Power, P = 1/f ( in m) = (n-1)/0.09
Now, this lens is in with conjunction with a concave mirror which then can be thought of as to be in conjunction with another thin lens
Power of concave mirror = P' = 1/f ( in m) = 2/R = 2/0.18 = 1/0.09
Net power of the combination = 2P + P' = 2(n-1)/0.09 + 1/0.09 = 1/0.05
n = 1.4