Q: A velocity-time plot shows a constant velocity of $$4\ \mathrm{m/s}$$ for 5 seconds, then a sudden jump to $$8\ \mathrm{m/s}$$ for the next 5 seconds. What is the total displacement after 10 seconds?

$$(4\ \mathrm{m/s} \times 5\ \mathrm{s}) + (8\ \mathrm{m/s} \times 5\ \mathrm{s}) = 60\ \mathrm{m}$$

Q: A projectile is launched at $$30\ \mathrm{m/s} at an $$angle of $$45^\circ$$ above the horizontal. What is the maximum height reached? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

$$\frac{(30 \sin 45^\$$circ)^2$$}{2 \times 9.8} = 16.5\ \mathrm{m}$$

Q: A $$2\ \mathrm{kg}$$ object moves at $$3\ \mathrm{m/s}$$ east and a $$1\ \mathrm{kg}$$ object moves at $$2\ \mathrm{m/s}$$ west. What is the total linear momentum of the system?

$$(2 \times 3) + (1 \times -2) = 4\ \mathrm{kg\cdot m/s}$$

Q: A force of $$10\ \mathrm{N}$$ acts on a $$2\ \mathrm{kg}$$ object for $$4\ \mathrm{s}. $$What is the change in velocity?

$$\frac{10 \times 4}{2} = 20\ \mathrm{m/s}$$

Question 1

Which of the following best describes a 'discrepant event' in the context of scientific investigations?

Accepted Answer

An event that contradicts or challenges existing expectations, prompting further inquiry.

Question 2

A student proposes the hypothesis: 'If a ball is dropped from a height, it will accelerate due to gravity.' Which characteristic makes this a testable hypothesis?

Accepted Answer

It can be measured and observed through experimentation.

Question 3

Which of the following correctly lists the steps of the scientific process?

Accepted Answer

Observation, Hypothesis, Experiment, Analysis, Conclusion

Question 4

Which tool would best measure the inertia of translation for a moving car?

Accepted Answer

A balance

Question 5

An object is moving in a straight line and suddenly the force acting on it is removed. According to Newton's First Law, what path will the object follow?

Accepted Answer

It will continue in a straight line at constant velocity.

Question 6

Which of the following is the SI unit for inertia of translation?

Accepted Answer

Kilogram ($$\mathrm{kg})$$

Question 7

A measuring instrument shows a reading of 5.2 cm. The smallest division on the instrument is 0.1 cm. What is the uncertainty of this measurement?

Accepted Answer

$$\pm 0.1\ \mathrm{cm}$$

Question 8

A runner completes three legs of a trip: 100 m east in 20 s, 50 m north in 10 s, and 100 m west in 20 s. What is the average speed for the entire trip?

Accepted Answer

$$\frac{250\ \mathrm{m}}{50\ \mathrm{s}} = 5\ \mathrm{m/s}$$

Question 9

Convert a speed of 120 inch/minute to meter/second.

Accepted Answer

$$0.0508\ \mathrm{m/s}$$

Question 10

A velocity-time plot shows a constant velocity of $$4\ \mathrm{m/s}$$ for 5 seconds, then a sudden jump to $$8\ \mathrm{m/s}$$ for the next 5 seconds. What is the total displacement after 10 seconds?

Accepted Answer

$$(4\ \mathrm{m/s} 	imes 5\ \mathrm{s}) + (8\ \mathrm{m/s} 	imes 5\ \mathrm{s}) = 60\ \mathrm{m}$$

Question 11

An object of mass $$2\ \mathrm{kg} is $$acted upon by a net force of $$10\ \mathrm{N}. $$What is its acceleration?

Accepted Answer

$$5\ \mathrm{m/s^2$}$$

Question 12

A ball weighs $$49\ \mathrm{N} on $$Earth. What is its inertial mass?

Accepted Answer

$$5\ \mathrm{kg}$$

Question 13

A skydiver of mass $$80\ \mathrm{kg}$$ falls through air and reaches terminal velocity. If the drag force is directly proportional to speed, and the weight is $$784\ \mathrm{N}$$, what is the terminal velocity if the proportionality constant is $$k = 14\ \mathrm{N\cdot s/m}$$?

Accepted Answer

$$56\ \mathrm{m/s}$$

Question 14

Which of the following is an example of an action-reaction pair according to Newton's Third Law?

Accepted Answer

A car pushes against the road, and the road pushes back on the car.

Question 15

A projectile is launched at $$30\ \mathrm{m/s} at an $$angle of $$45^\circ$$ above the horizontal. What is the maximum height reached? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$\frac{(30 \sin 45^\$$circ)^2$$}{2 	imes 9.8} = 16.5\ \mathrm{m}$$

Question 16

A $$2\ \mathrm{kg}$$ object moves at $$3\ \mathrm{m/s}$$ east and a $$1\ \mathrm{kg}$$ object moves at $$2\ \mathrm{m/s}$$ west. What is the total linear momentum of the system?

Accepted Answer

$$(2 	imes 3) + (1 	imes -2) = 4\ \mathrm{kg\cdot m/s}$$

Question 17

A force of $$10\ \mathrm{N}$$ acts on a $$2\ \mathrm{kg}$$ object for $$4\ \mathrm{s}. $$What is the change in velocity?

Accepted Answer

$$\frac{10 	imes 4}{2} = 20\ \mathrm{m/s}$$

Question 18

Why are work and energy measured in the same SI units?

Accepted Answer

Both represent the ability to cause change and are defined by $$\mathrm{J} = \mathrm{N} \cdot \mathrm{m}.$$

Question 19

A machine does $$500\ \mathrm{J} of $$useful work while consuming $$800\ \mathrm{J} of $$energy. What is its efficiency?

Accepted Answer

$$\frac{500}{800} 	imes 100\% = 62.5\%$$

Step-by-Step Study Guidance for Elementary Physics I (PHYS-1405-8)

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