A unit of energy equal to the work done when a force of one newton acts through a distance of one meter.
Important Points
The other common units for heat are-
BTU (Btu) - British Thermal Unit - also known as a "heat unit" in the United States.
Calorie: The amount of heat required to raise the temperature of one gram of water 1^{o}C.
Erg is a unit of energy.
It equal to the force of one dyne over a distance of one centimeter.
1 erg = 10^{-7} joule.
Watt is a unit (SI) of power.
It is equal to one joule of work performed per second.
1 horsepower = 746 watt
Key Points
1 joule = 0.14 calorie = 9.478 x 10^{-4} Btu.
4.184 joule of heat energy (or one calorie) is required to raise the temperature of a unit weight (1 g) of water from 0^{o}C to 1oC, or from 32^{o}F to 33.8^{o}F.
Equation of motion: The mathematical equations used to find the final velocity, displacements, time, etc of a moving object without considering force acting on it are called equations of motion.
These equations are only valid when the acceleration of the body is constant and they move on a straight line.
Where, V = final velocity, u = initial velocity, s = distance traveled by the body under motion, a = acceleration of body under motion, and t = time taken by the body under motion.
A bicyclist comes to a skidding stop in 10 m. During this process, the force on the bicycle due to the road is 200 N and is directly opposed to the motion. The work done by the cycle on the road is:
Zero
-2000 J
1 J
2000 J
Answer (Detailed Solution Below)
Option 1 : Zero
Basic Science and Engineering MCQ Question 6 Detailed Solution
Work is said to be done by a force when the body is displaced actually through some distance in the direction of the applied force.
Since the body is being displaced in the direction of F, therefore work done by the force in displacing the body through a distance s is given by:
\(W = \vec F \cdot \vec s\)
Or, W = Fs cos θ
Thus work done by a force is equal to the scalar or dot product of the force and the displacement of the body.
CALCULATION:
The Cycle has applied brakes. The tyre is now skidding. The person must have put some force on the pedals that the bike stops only after 10 m and not immediately(sudden stop).
Given that:
The Displacement D, of the cycle, is 10 m
The Frictional Force acting on the cycle is 200 N.
The Force the cycle applies will be equal to frictional force = 200 N.
The road does not move, D or displacement of the road is zero,
Weight is a force that acts at all times on all objects near or on earth.
Here given weight = 98 Newton. Weight = Object mass × Gravitational acceleration (g)
So, object mass = \({weight \over g}\) = \({98 \over 9.8}\) = 10 kg.
Important Points
g = gravitational acceleration = 9.8 m/s^{2} = 32 feet/s^{2}.
Newton discovered the relationship between the motion of the Moon and the motion of a body falling freely on Earth.
Gravity is far weaker than the other three fundamental forces (electromagnetic force, strong force, and weak force).
Gravity bends light.
Key Points
To leave Earth’s gravitational pull behind, an object must travel 7 miles/second.
At the center of the Earth, you would feel weightless.
When a force is applied to an object which causes displacement along the direction of force then the work is said to be done by that force.
The work done by a force is defined as "the product of the component of the applied force on the block in the direction of the displacement and the magnitude of this displacement" is called work done.
Additional Information
i.e., \(W = \vec F.d\vec x = Fdx\cos \theta \)
or in terms of magnitude, it can be given as
\(W\; = \;F \times s\)
Here both force and displacement will be along the same direction since force is causing this displacement thus Work done is a scalar quantity.
Here,
Force applied on object = F
Displacement of object = dx
Distance traveled by an object = s
The angle between Force and displacement = θ
Calculation:
Given that,
Person raised the box of weight 120 N through the height of 2 m
i.e., F = 120 N
x = 2 m
Thus from the above explanation, we can see that
Work = Force × Distance moved in the direction of the force
Machine Language is the language written as strings of binary 1's and Os.
It is the only language that a computer understands without using a translation program. A low-level language is a machine language.
Additional Information
Assembly Language:
An assembly language is a low-level programming language in which there is a very strong correspondence between the program's statements and the architecture's machine code instructions.
Each assembly language is specific to computer architecture and sometimes to an operating system.
Middle Ware
Middleware is software that enables one or more kinds of communication or connectivity between two or more applications or application components in a distributed network.
Confusion Points
Both Machine language and Assembly language are low-level languages. But the machine language is even lower than the assembly language. Hence machine language is the best possible answer.
Carbon footprint is the total amount of greenhouse gases released into the atmosphere as a result of the activities of a particular individual, organization, or community.
It is usually expressed in equivalent tons of carbon dioxide (CO_{2}).
Important Points:
Carbon footprint is the sum of all emissions of CO_{2} (carbon dioxide), which were induced by all activities in a given time frame.
Usually, a carbon footprint is calculated for the time period of a year.
The ampere, symbol A, is the SI unit of electric current.
It is defined by taking the fixed numerical value of the elementary charge e to be 1.602 176 634 ×10^{−19} when expressed in unit C, which is equal to A.s.
Additional Information
The seven SI base units, which are comprised of:
Length - meter (m)
Time - second (s)
Amount of substance - mole (mole)
Electric current - ampere (A)
Temperature - kelvin (K)
Luminous intensity - candela (cd)
Mass - kilogram (kg)
Ohm(Ω) is the SI unit of Electric Resistance.
Volt (V) is the SI unit of Electric Potential.
Ohmmeter, an instrument for measuring electrical resistance, which is expressed in ohms.
A wooden block of mass m_{1} kg accelerates at 10 ms^{-2} when a force of 5 N acts on it. Another block of mass m_{2} kg accelerates at 20 ms^{-2} when the same force acts on it. If both the blocks are tied together and the same force acts on their combination, the acceleration will be about:
6.67 ms^{-2}
1.67 ms^{-2}
5.67 ms^{-2}
4.67 ms^{-2}
Answer (Detailed Solution Below)
Option 1 : 6.67 ms^{-2}
Basic Science and Engineering MCQ Question 20 Detailed Solution