Answer:
a) Option D
b) Option A
Explanation:
a) Option D
Because a massive car will have more inertia which will make the car move faster but a massive car simultaneously will have more friction thereby restricting its movement in the forward direction. Hence, all the three cars will move equal distance.
b) Option A, Car F
Being most massive car, the frictional force required to stop the car will be highest.
Answer:
PART A)
External force will be 75 N
PART B)
distance moved will be 1.125 m
Explanation:
PART A)
Given that net force on the mower is

now we also know that friction force due to ground is given as

now we have



so external force will be 75 N
PART B)
deceleration due to friction when external force is removed from it


now we can find the distance by kinematics



so the distance moved will be 1.125 m
Work done against gravity to climb upwards is always stored in the form of gravitational potential energy
so we can say

here h = vertical height raised
so here we know that

here we have

now from above equation


so work done will be given by above value
Answer:
6) False
7) True
8) False
9) False
10) False
11) True
12) True
13) True
14) True
Explanation:
The spacing between two energy levels in an atom shows the energy difference between them. Clearly, B has a greater value of ∆E compared to A. This implies that the wavelength emitted by B is greater than A while B will emit fewer, more energetic photons.
When atoms jump from lower to higher energy levels, photons are absorbed. The kinetic energy of the incident photon determines the frequency, wavelength and colour of light emitted by the atom.
The energy level to which an atom is excited is determined by the kinetic energy of the incident electron. As the voltage increases, the kinetic energy of the electron increases, the further the atom is from the source of free electrons, the greater the required kinetic energy of free electron. When electrons are excited to higher energy levels, they must return to ground state.