Answer:
A. Atoms are the smallest unit of an element.
Explanation:
The correct statement from the given choices is that atoms are the smallest unit of an element.
Atoms are the smallest particles that takes part in chemical reactions and they are made up of protons, neutrons and electrons.
- Elements are distinct substances that cannot be split up into simpler substances.
- They are made up of only one kind of atoms.
- Elements are not changed into atoms by chemical reactions.
- In chemical reactions, atoms simply recombine.
The direction of this vector is 170° from the positive x-axis.
- Vectors are physical quantities with both magnitude and direction
- To identify the direction, we usually use angles and take a reference axis
- The vector in the diagram is 80° to the left of the positive y-axis, so the direction of the vector is 80° + 90° = 170° anti-clockwise from the positive x-axis.
- Scalars are physical quantities which have only magnitude
- Examples of vector quantities are displacement, velocity, acceleration, force etc
- Examples of scalar quantities are distance, speed, volume, density, mass, time etc
- The direction of the given vector is 170° from the positive x-axis.
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Speed is a derived term that is the result when distance or displacement is divided by unit time. Speed is a scalar unit which means it only includes magnitude not direction, thus always positive. The answer thus are the three choices given above.
The force exerted on the tires of a car that directly accelerate it along a road is exerted by the road friction.
<h3>What is force?</h3>
Force is defined as the product of mass and acceleration of an object.
Friction is defined as the force that resists the movement of an object over another.
Therefore, the force exerted on the tires of a car that directly accelerate it along a road is exerted by the road friction.
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