题目

MUF0121 Physics Unit 1 - Semester 2, 2025 2.6 Equations of Motion quiz

匹配题

You need to solve each of these problems. Which expression will you use to get the correct answer? 1: A car travelling at 20 m/s puts on its brakes and decelerates by 5 m/s² for 3 s. What distance did it move in this time? 2: It takes a car ten seconds to speed up from 20 m/s to 30 m/s. How far did it move in this time? 3: A jet plane reached a speed of 300 m/s after accelerating at 15 m/s² using its afterburners for 2.7 seconds. How far did it go in this time?

选项

A.ut + ½at²

B.½ (u +v) t

C.(v² - u²)/2 x

D.vt - ½at²

E.u² + ½at²

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标准答案

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思路分析

Here’s how to assess each candidate expression against the three problems, taking into account constant acceleration and the standard kinematic formulas. Option 1: ut + ½ at² - This is the displacement formula s = u t + (1/2) a t² for motion with constant acceleration, where u is the initial velocity, a is acceleration, and t is time. It applies to all three scenarios provided: (i) decelerating from 20 m/s with a = -5 m/s² for t = 3 s, (ii) accelerating ......Login to view full explanation