Question 1

Hooke's law for restoring the force of an oscillating system is F = -kx. If F is a force (unit N) and x is displacement (unit m), then the unit of the constant k is kg m²/s².

Accepted Answer

The unit of the constant k in Hooke's law is N/m (newtons per meter), which simplifies to kg/s², not kg m²/s².

Question 2

Any of the following numbers is a correct way to write 96300000 in scientific notation: 963 × 10⁵, 96.3 × 10⁶, or 9.63 × 10⁷.

Accepted Answer

The correct scientific notation for 96300000 is 9.63 × 10^7.

Question 3

A cylindrical water tank holds 650 L of water. The volume of a cylinder is given by V = ðr²h (r is radius, h is height). How much water (in litres) could the tank hold if the radius was doubled and the height reduced to half?

Accepted Answer

The answer of A cylindrical water tank holds 650 L...

Question 4

You are measuring your weight on a scale.
(a) You are measuring your weight on a digital scale which can even show one decimal. The measurement shows 120.7 lb. Within what limits is your true weight likely to be?
(b) You are measuring your weight on another type of scale that has a known uncertainty of ±0.5 lb and shows 121 lb. Within what limits is your true weight likely to be?

Accepted Answer

The answer of You are measuring your weight on a...

Question 5

Estimate the number of hairs on your head, if you counted 50 hairs on a 5 mm × 5 mm area. State your assumptions.

Accepted Answer

The answer of Estimate the number of hairs on your...

Question 6

Radioactive decay is described with the following law: N = N₀ × 2^-^ë^t, where N is the number of nuclei, N₀ is the original number of nuclei at the start of the process, t is time needed for N0 to decay to N, and ë is a radioactive constant of a particular element. What are the units of ë? If the radioactive constant of another element is larger, does that element require a shorter or longer time to perform the same decay?

Accepted Answer

The answer of Radioactive decay is described with the following...

Question 7

Numbers 0.025 and 25 have the same number of significant figures.

Accepted Answer

0.025 has 3 significant figures (2, 5, and the zero between them). 25 also has 3 significant figures (2, 5, and the zero at the end).

Question 8

Some astrologers claim that the gravitational influence of Mars can affect a child during birth. Gravitational force is linearly proportional to the masses of two bodies and decreases with the square of the distance between those bodies. Compare the influence of Mars (at a distance is 7.8 × 10⁷ km from Earth) and a 70 kg doctor at a distance of 0.1 m, on a 3 kg baby. The mass of Mars is 6.42 × 10²³ kg, and the universal gravitational constant is G = 6.67300 × 10^-11 m³ kg^-1s^-2.

Accepted Answer

The answer of Some astrologers claim that the gravitational influence...

Question 9

The masses of the human brain and body are related as mass_brain is proportional to (mass_body)^0.68. Find the brain mass of a dolphin: (a) if we assume that the dolphin is as intelligent as a human, and (b) if we assume that it is as intelligent as a chimpanzee. Compare your results to the real value from the table and draw a conclusion about its intelligence ranking.

Accepted Answer

The answer of The masses of the human brain and...

Question 10

Nerve fibres conduct impulses with a speed of 72 m/s in rats, which is faster than the 72 km/h speed of conduction in squids.

Accepted Answer

The given statement correctly states that nerve fibres conduct impulses faster in rats (72 m/s) than in squids (72 km/h).

Question 11

When choosing between two models that explain a physical principle with equal success, but differ in complexity of the explanation, how do we choose the more plausible model?

Accepted Answer

The answer of When choosing between two models that explain...

Question 12

Calculate both the sum of and the difference between the following two numbers: 1.04 × 10^-5 m and 7.7 × 10^-7 m. Express your results using correct units, number of significant digits, and scientific notation.

Accepted Answer

The answer of Calculate both the sum of and the...

Question 13

Numbers 20 and 20.0 have the same number of significant figures.

Accepted Answer

The number 20 typically has one significant figure (assuming it's not specified otherwise, as in scientific notation), while 20.0 has three significant figures because the decimal point specifies that the zeros are significant.

Question 14

Earth's equator, with a circumference of around 40000 km, is longer than the total length of capillaries in the human body (6 × 10⁹ cm).

Accepted Answer

The total length of capillaries in the human body is estimated to be between 40,000 to 100,000 kilometers, which is much longer than the Earth's equator circumference of around 40,000 kilometers.

Question 15

Average human heartbeat is 75/minute. How many heartbeats has a 20-year-old student had since birth?

Accepted Answer

The answer of Average human heartbeat is 75/minute. How many...

Question 16

In creating a model that would explain a certain physical concept, observations and collected data are most useful for proving that the model is a true representation of a concept.

Accepted Answer

Observations and collected data are crucial for testing and refining a model, but they cannot prove a model to be a true representation of a concept, only support its validity. Models are simplifications and can always be subject to revisions with new evidence.

Question 17

The speed of light is 3 × 10⁸ m/s. The distance between Earth and the Sun is roughly 150 million kilometres. How long does it take for light to travel from the Sun to Earth? Express the result in seconds, minutes, hours, and days. Which unit is most appropriate?

Accepted Answer

The answer of The speed of light is 3 ×...

Question 18

When adding or subtracting numbers, the result has the same precision as the least precise number used in the calculation.

Accepted Answer

In calculations involving addition or subtraction, the result should not have more decimal places than the least precise measurement used in the calculation. This rule ensures that the reported result does not imply a greater level of precision than the measurements allow.

Question 19

The calculator can hold only a few significant digits. When adding a set of positive numbers of widely varying magnitude on a calculator, in order to get the result with the highest precision, one should start at the largest number and add successively smaller ones.

Accepted Answer

Starting with the smallest numbers and adding them up before adding the larger numbers helps in preserving the precision of the smaller numbers, as their contribution might be lost due to rounding errors when added after the larger numbers.

Question 20

The smallest power of 10 quoted in a result is a good indicator of the precision of the measurement.

Accepted Answer

The smallest power of 10 quoted in a result, often referred to as the least significant figure, indicates the precision of the measurement by showing the smallest unit or fraction of a unit that has been measured, thus reflecting the level of detail and accuracy in the measurement.

Quiz 1: Physics and the Life Sciences

Hooke's law for restoring the force of an oscillating system is F = -kx. If F is a force (unit N) and x is displacement (unit m), then the unit of the constant k is kg m2/s2.

Any of the following numbers is a correct way to write 96300000 in scientific notation: 963 × 105, 96.3 × 106, or 9.63 × 107.

A cylindrical water tank holds 650 L of water. The volume of a cylinder is given by V = ðr2h (r is radius, h is height). How much water (in litres) could the tank hold if the radius was doubled and the height reduced to half?