Answer:
The time is 5.10 sec.
Explanation:
Given that,
Component of velocity are 30 m/s and 40 m/s.
We need to calculate the resultant velocity
Using formula of resultant velocity

Put the value into the formula

[
We need to calculate the time
Using equation of motion



Put the value into the formula


Hence, The time is 5.10 sec.
Answer:
Sound and light are similar in that both are forms of energy that travel in waves. They both have properties of wavelength, freqency and amplitude. Here are some differences: Sound can only travel through a medium (substance) while light can travel through empty space.
Answer : The energy of one photon of hydrogen atom is, 
Explanation :
First we have to calculate the wavelength of hydrogen atom.
Using Rydberg's Equation:

Where,
= Wavelength of radiation
= Rydberg's Constant = 10973731.6 m⁻¹
= Higher energy level = 3
= Lower energy level = 2
Putting the values, in above equation, we get:


Now we have to calculate the energy.

where,
h = Planck's constant = 
c = speed of light = 
= wavelength = 
Putting the values, in this formula, we get:


Therefore, the energy of one photon of hydrogen atom is, 
Answer:
frequency or wavelength
Explanation:
this is why the electromagnetic spectrum has a decreasing wavelength and increasing frequency
Answer:
x = 5.79 m
Explanation:
given,
mass of the car = 39000 Kg
spring constant = 5.7 x 10⁵ N/m
acceleration due to gravity = 9.8 m/s²
height of the track = 25 m
length of spring compressed = ?
using conservation of energy
potential energy is converted into spring energy




x = 5.79 m
the spring is compressed to x = 5.79 m to stop the car.