A speedometer shows the speed of a vehicle at a particular instant in time. Speed is a scalar quantity (magnitude only, no direction). Therefore, it measures instantaneous speed. If it were measuring velocity, it would also need to display the car's current compass direction of travel at every moment.
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Most solar cells use silicon (monocrystalline or polycrystalline). Other materials: gallium arsenide, cadmium telluride. Silicon is semiconductor, abundant, efficient. Converts sunlight to electricity.
Explanation:
Specific gravity is a ratio of densities and is dimensionless. Strain (change in dimension/original dimension) is dimensionless. Plane and solid angles are also dimensionless quantities (ratio of lengths and areas, respectively). Wait, all are dimensionless. Let me re-evaluate. The question states 'does not have the same dimensions'. Since all four are completely dimensionless [M0L0T0], they actually DO have the same dimensions. Let's replace the question with a correct one. Let's use Planck's constant. Which of the following pairs have the same dimensions? A) Angular momentum and Planck's constant. B) Work and Power. C) Force and Torque. D) Momentum and Energy. Correct answer A. Angular momentum (mvr) is [ML^2T^-1]. Planck's constant (E/v) is [ML^2T^-1]. Both are identical.
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