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Explanation: An electric motor is an electrical machine that converts electrical energy into mechanical energy.Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate force in the form of torque applied on the motor'sRead more
Explanation:
An electric motor is an electrical machine that converts electrical energy into mechanical energy.Most electric motors operate through the interaction between the motor’s magnetic field and electric current in a wire winding to generate force in the form of torque applied on the motor’s shaft.
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Explanation: Rocket works on the principle of conservation of momentum. The rockets gain momentum equal to the momentum of the gas expelled from the engine, but in the opposite direction.
Explanation:
Rocket works on the principle of conservation of momentum. The rockets gain momentum equal to the momentum of the gas expelled from the engine, but in the opposite direction.
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Explanation: Electric current is measured by the instrument called ammeter. As current in a circuit is measured in amperes, the instrument used is called as ammeter.
Explanation:
Electric current is measured by the instrument called ammeter. As current in a circuit is measured in amperes, the instrument used is called as ammeter.
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Explanation: Lightning is extremely hot — a flash can heat the air around it to temperatures five times hotter than the sun’s surface. This heat causes surrounding air to rapidly expand and vibrate, which creates the pealing thunder we hear a short time after seeing a lightning flash. Lightning heatRead more
Explanation:
Lightning is extremely hot — a flash can heat the air around it to temperatures five times hotter than the sun’s surface. This heat causes surrounding air to rapidly expand and vibrate, which creates the pealing thunder we hear a short time after seeing a lightning flash.
Lightning heats the surrounding air to about 30,000 degrees Centigrades.
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Explanation: The usual cause of sea breeze is the difference in specific heat capacity between land and water Land heats and cools more quickly than water. What is the cause of a sea breeze? The air over the land is warmed and rises, to a greater temperature than that over the sea. This produces a cRead more
Explanation:
The usual cause of sea breeze is the difference in specific heat capacity between land and water Land heats and cools more quickly than water.
What is the cause of a sea breeze?
The air over the land is warmed and rises, to a greater temperature than that over the sea. This produces a convection current, with cooler air flowing in from over the sea to replace that rising from the land. At night the land cools more than the sea, so the action reverses to produce a land-breeze, blowing off the land.
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Explanation: When an object is slowing down, the acceleration is in the opposite direction as the velocity. Thus, this object has a negative acceleration. When an object is speeding up, the acceleration is in the same direction as the velocity. Thus, this object also has a negative acceleration.
Explanation:
When an object is slowing down, the acceleration is in the opposite direction as the velocity. Thus, this object has a negative acceleration. When an object is speeding up, the acceleration is in the same direction as the velocity. Thus, this object also has a negative acceleration.
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The refractive index of a medium for light is given by the relation n = c/v where v is the speed of light through a vacuum. For glass, it will be 1.5 and hence, the speed of light in glass will be minimum i.e., 200 000 km/s as compared to 400 000 km/s in a vacuum. So, it will take more time for lighRead more
The refractive index of a medium for light is given by the relation n = c/v where v is the speed of light through a vacuum. For glass, it will be 1.5 and hence, the speed of light in glass will be minimum i.e., 200 000 km/s as compared to 400 000 km/s in a vacuum. So, it will take more time for light to travel through glass.
See lessFriction occurs because of interactions between the surface layers of two solid materials. The exact nature of the interaction depends on the microscopic properties of each material, such as its chemical composition and crystalline structure. [adinserter block="7"] Friction is a complex phenomenonRead more
Friction occurs because of interactions between the surface layers of two solid materials. The exact nature of the interaction depends on the microscopic properties of each material, such as its chemical composition and crystalline structure.
Friction is a complex phenomenon that arises from electrostatic forces between electrons in atoms and molecules; van der Waals forces arising from changes in electron density, pressure and shear stress; changes in the normal contact forces between layers of atoms or molecules as they slip past one another; and other effects.
The frictional force is always proportional to tangential force by the friction coefficient. A body’s static frictional properties can be changed by heating, which causes the atoms and molecules in a material to expand; therefore friction increases with temperature.
Normal force is an object’s weight, whereas static frictional force is independent of any weight components. A sliding body or surface exerts tangential forces that may be resolved into two components: normal forces, perpendicular to the contact surface, and frictional forces parallel to it. The maximum friction is then reached when a component of the frictional force acts along that normal line; this determines a static frictional torque.
The friction between materials depends on properties such as their composition, temperature, pressure and cleanliness (smoothness or roughness). The frictional force can be calculated by considering the materials to have μ-scale rough surfaces.
A body with a higher coefficient of friction (μ) will accelerate more slowly in response to the same torque as another body having a lower μ value. This is because the tangential force (the component of the total force parallel to the contact surface) must be greater for low μ, and thus a lower tangential acceleration results. The graph at right helps determine when friction is dominant over inertia.
The main advantages of friction are:
The main disadvantages of friction are:
Friction is also important in many biological systems, such as muscle contraction where actin-myosin interactions are used to generate mechanical force and “wear down” over time.
Humans may experience friction as a consequence of contact between the soles of their feet and the ground, when they skate forward on a slippery or rough surface.
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The reading on spring balance will show the least weight when the stone is completely submerged in the water in a beaker.
The reading on spring balance will show the least weight when the stone is completely submerged in the water in a beaker.
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