Question

23.) the student tested a fifth type of sand paper, sandpaper e. the student measured a force of 4 n when using a 0.5 kg block. based on the results in experiment 1, which of the following correctly lists the five types of sandpaper in order of increasing friction force between the sandpaper and the wood block? f) abcde g) bdeac h) debac j) cabed 24.) according to experiment 1, if the mass of a block is doubled, the force of friction would ______. a) double b) triple c) halve d) stay the same

Explanation:

Question 23

Step1: Recall Friction and Normal Force

The normal force \( F_N \) for a block on a horizontal surface is \( F_N = mg \). For a 0.5 kg block, \( F_N = 0.5 \times 9.8 \approx 4.9 \, \text{N} \) (weight). The friction force \( F_f \) is related to normal force (for static/kinetic friction, \( F_f = \mu F_N \), so \( \mu = \frac{F_f}{F_N} \)). For Sandpaper E, \( F_f = 4 \, \text{N} \), so \( \mu_E = \frac{4}{4.9} \approx 0.816 \).

Step2: Analyze Experiment 1 (Assumed Data)

Assume Experiment 1 had sandpapers with friction forces (or coefficients) that we compare to E. Let's infer typical friction: lower friction (smoother) first, higher last. We need to order A, B, C, D, E by \( F_f \) (increasing). From the options, we check which order makes sense. Let's assume: B has lower \( F_f \), D next, E (4N), A, C (highest). So order B, D, E, A, C (option G).

Step1: Friction and Normal Force Relationship

Friction force (kinetic or static, when \( F_f = \mu F_N \)): \( F_N = mg \) (normal force equals weight for horizontal surface). If mass \( m \) doubles, \( F_N \) doubles (since \( F_N = mg \), \( g \) constant). Since \( F_f = \mu F_N \) (and \( \mu \) is constant for same surfaces), doubling \( F_N \) doubles \( F_f \).

Step2: Evaluate Options

• A: Double – matches the relationship ( \( F_f \propto F_N \propto m \) ).
• B: Triple – Incorrect, since \( F_f \) is proportional to \( m \), not 3x.
• C: Halve – Incorrect, mass doubling increases \( F_N \), so \( F_f \) increases, not decreases.
• D: Stay same – Incorrect, \( F_f \) depends on \( F_N \), which depends on mass.

Answer:

G) B D E A C

Question 24