A helicopter lifts a 72 kg astronaut 15 m vertically from the ocean by means of a cable. The acceleration of the astronaut is g/
2 answers:
Answer:
a)
b)
c)
d)
Explanation:
Given:
- mass of the astronaut,
- vertical displacement of the astronaut,
- acceleration of the astronaut while the lift,
a)
<u>Now the force of lift by the helicopter:</u>
Here the lift force is the resultant of the force of gravity being overcome by the force of helicopter.
where:
force by the helicopter
force of gravity
b)
The gravitational force on the astronaut:
d)
Since the astronaut has been picked from an ocean we assume her initial velocity to be zero,
using equation of motion:
c)
Hence the kinetic energy:
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Before going to answer this question first we have to understand reflection and laws of reflection.
Reflection is the optical phenomenon in which light will bounce back to the same medium from which it had originated .
Whenever a light ray will incident on a mirror or any reflecting surface, it will be reflected. The ray which falls on the reflecting surface is called incident ray and the ray which is reflected is called reflected ray.
Let us consider a normal to the point of incidence.The angle made by incident ray with the normal is called angle of incidence.Let it be denoted as[ i ]
The angle made by the reflected ray with the normal is called angle of incidence.Let it be denoted as [r]
There are two types of reflection.One is called regular and other one is called as irregular.The laws of reflection is valid for both the types of reflection.
There are two laws of reflection.
FIRST LAW -It states that the incident ray,reflected ray and the normal to the point of incidence,all lie in one plane.
SECOND LAW- It states that that the angle of incidence is equal to the angle of reflection irrespective of the type of reflection.i.e i =r
Hence the correct answer will be angle of reflection.
