Explanation

When a book is stationary, the upward normal force from the table equals the downward gravitational force.

These balanced forces result in no motion, keeping the book at rest.

Explanation

A magnetic field exerts a force perpendicular to the motion of the charged particle, changing its direction but not its speed.

Since no work is done by the magnetic field, the kinetic energy stays constant.

Explanation

An electric field does work on a charge, causing it to gain or lose energy (kinetic or potential).

A magnetic field can change the direction of a moving charge.

Explanation

In a solid metal conductor, electric current is due to the flow of free electrons.

Electrons are negatively charged particles that move through the metal to create current.

Explanation

1 kilowatt hour (kWh) = 3.6 million joules (3.6 × 10⁶ J)

1 joule = 10⁷ ergs, so both joule and erg are much smaller than kilowatt hour.

Hence, Kilowatt hour is the biggest unit.

Explanation

Explanation

"3x" usually represents 3 rectangles (each representing x).

"+2" typically means 2 small unit squares (each representing 1).

So, a model showing 3 long bars and 2 small squares matches 3x + 2.

Explanation

Given A = p + prt, we need to solve for t.

Step 1: Subtract p from both sides

A - p = prt

Step 2: Divide both sides by pr

(A - p) / pr = t

The answer is A-p/pr.

Explanation

The initial population is 2¹⁶ insects.

If the population doubles, the new population will be 2 * 2¹⁶ = 2¹⁷.

Explanation

Step 1: Convert 2.5 × 10^-1 to a fraction

2.5 × 10^-1 = 0.25 = 1/4.

Step 2: Calculate 1/2 + 1/4

To add these fractions, find a common denominator, which is 4. 1/2 = 2/4. So, 2/4 + 1/4 = 3/4.