Physics 1 · Unit 8 · Paper 1

Fluids unit test

A test on this unit alone, marked as a percentage and a letter grade — for the test your class is actually sitting, rather than for May. Answer everything, then submit once: seeing the answer to question 3 before attempting question 4 makes the final percentage meaningless.

Paper 1 Paper 2 Paper 3

Each paper is built from this unit’s 45 terms and is the same for everyone, so a teacher can assign “Unit 8, Paper 1” and every student sits the identical test. Multiple choice is marked objectively; the written sections you mark yourself against the model answer and rubric.

Suggested time 35 min 32 points0/17 attempted

Why a lower hole shoots further

Float, sink or hover

Why pressure does not depend on container shape

Buoyancy is a pressure difference

Continuity before Bernoulli

Applying Bernoulli and continuity together

Where Bernoulli's equation fails

Bernoulli's terms are energies per unit volume

Why a denser fluid means less submerged

Apparent weight in a fluid

Fraction submerged

Pressure with depth

Short answer 1. Define or explain: Ideal fluid

3 pts

Short answer 2. Define or explain: Density of water

3 pts

Short answer 3. Define or explain: Archimedes' principle

3 pts

Short answer 4. Define or explain: Streamline versus turbulent flow

3 pts

Free response

8 pts

QUALITATIVE/QUANTITATIVE TRANSLATION (Question 4, 8 points). In Scenario 1, a swimmer holds a block of mass m at rest, fully submerged in a tank of freshwater with density ρ1; when released from rest the block accelerates upward with initial acceleration a1. In Scenario 2 the swimmer holds the same block at rest in a tank of salt water with density ρ2 > ρ1; released again, the block accelerates upward with initial acceleration a2. All frictional forces are negligible.

A. Indicate whether a1 is greater than, less than, or equal to a2, and justify your answer in terms of ALL forces exerted on the block in each scenario, using qualitative reasoning beyond referencing equations.

B. For the general case of a block of mass m and volume V completely submerged in a fluid of density ρ: starting with Newton’s second law, derive an expression for the initial upward acceleration a of the block when released from rest, in terms of m, V, ρ, and physical constants, as appropriate.

C. Indicate whether the expression derived in part B is or is not consistent with the claim made in part A, and briefly justify by referencing the derivation.