Answer:
The driver's average velocity is 82.35 km/h.
Explanation:
Given:
The motion of the driver can be divided into 3 parts:
i. Displacement of the driver in 1.5 hours = 135 km
ii. Rest for 45 minutes.
iii. Displacement in next 2 hours = 215 km
The direction of motion remains same (east).
Now, total displacement of the driver is,
km.
Rest time is 45 minutes. Converting it to hours, we need to use the conversion factor
hour.
So, 45 minutes in hours is equal to
hours.
Now, total time taken for the complete journey is, 
Average velocity is given as:

Therefore, the driver's average velocity is 82.35 km/h
Answer:
according to newtons second law of motion,
Force = mass * acceleration
The acceleration of the body is directly proportional to the net force acting on the body and inversely proportional to the mass of the body.
I. e mass and acceleration are directly proportional to each other.
Answer: 0.55 m/s
Explanation:
This situation is related to projectile motion (also called parabolic motion), where the main equations are as follows:
(1)
(2)
Where:
is the horizontal displacement of the pencil
is the pencil's initial velocity
since we are told the pencil rolls <u>horizontally</u> before falling
is the time since the pencil falls until it hits the ground
is the initial height of the pencil
is the final height of the pencil (when it finally hits the ground)
is the acceleration due gravity, always acting vertically downwards
Begining with (1):
(3)
(4)
Finding
from (2):
(5)
(6)
Substituting (6) in (4):
(7)
Isolating
:
(8)
(9)
Finally:
Answer:
120N
Explanation:
Newton's second law formula: F= ma
given that m = 10 kg, a = 12 m/s^2
F = ma = 10 kg * 12 m/s^2 = 120 kgm/s^2 = 120 N
Answer:
Initial state Final state
3 ⇒ 2
3 ⇒ 1
2 ⇒ 1
Explanation:
For this exercise we must use Bohr's atomic model
E = - 13.606 / n²
where is the value of 13.606 eV is the energy of the ground state and n is the integer.
The energy acquired by the electron in units of electron volt (eV)
E = e V
E = 12.5 eV
all this energy is used to transfer an electron from the ground state to an excited state
ΔE = 13.6060 (1 / n₀² - 1 / n²)
the ground state has n₀ = 1
ΔE = 13.606 (1 - 1/n²)
1 /n² = 1 - ΔE/13,606
1 / n² = 1 - 12.5 / 13.606
1 / n² = 0.08129
n = √(1 / 0.08129)
n = 3.5
since n is an integer, maximun is
n = 3
because it cannot give more energy than the electron has
From this level there can be transition to reach the base state.
Initial state Final state
3 ⇒ 2
3 ⇒ 1
2 ⇒ 1