Physics Word Problems: Ecosystems

Ecosystems Word Problems

College Physics Ecosystems Word Problems Challenging 10 Questions 6 Views

Classroom Worksheet

Physics Word Problems: Ecosystems

Ecosystems Word Problems

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Grade: College

Subject: Physics

Topic: Ecosystems

Time: 20 Minutes

Difficulty: Challenging

Questions: 10

Instructions:
Solve each word problem by showing your reasoning and using appropriate physics concepts, formulas, and units. Assume standard values when needed and state any assumptions you make. Answers should be clear, complete, and classroom-friendly.

Skills Practiced:

Ecosystems
Physics
Critical Thinking
Problem Solving

1Question

A 12 W LED lamp is used to illuminate a terrarium for 5.0 hours each day. How much electrical energy does the lamp consume in one day, in joules?

2Question

A research team uses a 75 W water pump to circulate water in a small wetland habitat for 4.0 hours. How much energy does the pump use, in kilowatt-hours and in joules?

3Question

A solar panel array provides an average power of 180 W to a remote ecosystem sensor station for 6.0 hours per day. How much energy is delivered each day, and what average power would be needed if the same energy had to be supplied in only 3.0 hours?

4Question

A 2.5 kg battery pack is lifted vertically 1.8 m to mount a camera above a forest floor. How much gravitational potential energy does the pack gain? Use g = 9.8 m/s².

5Question

A small animal of mass 0.80 kg runs at 3.5 m/s across a meadow. What is its kinetic energy? If its speed doubles, by what factor does its kinetic energy change?

6Question

A stream drops 4.2 m over a waterfall and carries 0.60 kg of water per second through a turbine. Assuming all gravitational potential energy becomes useful energy, what power is available from the falling water? Use g = 9.8 m/s².

7Question

A predator-prey ecosystem has 15 kJ of chemical energy available at the producer level each day. If only 12% of that energy is transferred to primary consumers and then 18% of the primary-consumer energy is transferred to secondary consumers, how much energy reaches the secondary consumers each day?

8Question

An ecosystem monitor records that a 20.0 kg piece of floating debris moves from rest to 1.2 m/s after being pushed by a current over a distance of 3.0 m. Assuming constant acceleration, what net force acted on the debris?

9Question

A thermal camera on a wildlife reserve consumes 48 W and operates continuously for 10 days. The camera is powered by a battery system with 80% efficiency. How much electrical energy must the battery system store to keep the camera running for the full 10 days?

10Question

A graduate student is designing a self-sustaining wetland observatory. The observatory needs 2.0 kWh per day for sensors, 1.5 kWh per day for data transmission, and 0.50 kWh per day for lighting. A solar array produces an average of 220 W for 8.0 hours per day, and the battery storage is 90% efficient on both charging and discharging combined. Does the solar array provide enough energy for one day of operation? Show your calculation.

Answer Key

#	Answer
1	E = Pt = (12 J/s)(5.0 h)(3600 s/h) = 2.16 × 10^5 J
2	Energy = 75 W × 4.0 h = 300 Wh = 0.30 kWh; in joules: (75 J/s)(4.0 × 3600 s) = 1.08 × 10^6 J
3	Daily energy: E = Pt = (180 W)(6.0 h) = 1080 Wh = 1.08 kWh. Required power in 3.0 h: P = E/t = 1080 Wh / 3.0 h = 360 W
4	ΔU = mgh = (2.5)(9.8)(1.8) = 44.1 J ≈ 44 J
5	KE = 1/2 mv² = 0.5(0.80)(3.5²) = 4.9 J. If speed doubles, kinetic energy increases by a factor of 4.
6	Power = ṁgh = (0.60 kg/s)(9.8)(4.2) = 24.7 W ≈ 25 W
7	Primary consumers: 0.12 × 15 kJ = 1.8 kJ. Secondary consumers: 0.18 × 1.8 kJ = 0.324 kJ = 324 J
8	Use v² = 2ad: a = v²/(2d) = 1.2²/(2×3.0) = 0.24 m/s². Then F = ma = (20.0)(0.24) = 4.8 N
9	Useful energy needed: Eout = 48 W × (10 × 24 h) = 11,520 Wh = 11.52 kWh. With 80% efficiency, Ein = Eout/0.80 = 14.4 kWh. In joules: 14.4 × 3.6 × 10^6 = 5.18 × 10^7 J
10	Daily demand = 2.0 + 1.5 + 0.50 = 4.0 kWh. Solar production = 220 W × 8.0 h = 1760 Wh = 1.76 kWh. After 90% efficiency, usable energy = 1.76 × 0.90 = 1.584 kWh. Since 1.584 kWh < 4.0 kWh, the solar array does not provide enough energy for one day.