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spayn [35]
3 years ago
15

A student is gliding along on a scooter at a comfortable 2.8 m/s when Mr. Jones walks around the corner and the two collide. If

the student is brought to rest in 0.15 s, what is their acceleration (hint: should it be acceleration or deceleration)?
Physics
1 answer:
faltersainse [42]3 years ago
6 0

Answer:

Their deceleration is - 19 \frac{m}{s^{2} }

Explanation:

Acceleration is a quantity that indicates how the speed of the object changes over time. In other words, acceleration is a vector quantity that relates changes in velocity to the time it takes to occur. It is normally represented by the letter a and its unit of measurement, in the International System it is meters per second squared \frac{m}{s^{2} }.

The mathematical expression for the acceleration is:

a=\frac{final speed - initial speed}{final instant - initial instant}

In this case:

  • final speed= 0 \frac{m}{s}
  • initial speed= 2.8 \frac{m}{s}
  • final instant=0.15 s
  • initial instant= 0 s

Replacing:

a=\frac{0 \frac{m}{s} - 2.8\frac{m}{s} }{0.15 s - 0s}

a= -18. 667 \frac{m}{s^{2} } ≅ -19 \frac{m}{s^{2} }

Deceleration is a quantity that expresses the passage of a moving body from one speed to a lower speed. Mathematically it is calculated as the acceleration but the result will be a negative acceleration.

<u><em>Their deceleration is - 19 </em></u>\frac{m}{s^{2} }<u><em></em></u>

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An object is dropped from a platform 100 feet high. Ignoring wind resistance, what will its speed be when it reaches the ground?
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<span>y = 0 + 0t + ½gt² </span>
<span>y = ½gt² </span>

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<span>in the ft - lb - s system </span>

<span>y = -100 ft </span>
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A system gains 757 kJ757 kJ of heat, resulting in a change in internal energy of the system equal to +176 kJ.+176 kJ. How much w
Alecsey [184]

Answer:

581 kJ, work was done by the system

Explanation:

According to the first law of thermodynamics:

\Delta U = Q-W

where

\Delta U is the change in internal energy of the system

Q is the heat absorbed by the system (positive if absorbed, negative if released)

W is the work done by the system (positive if done by the system, negative if done by the surrounding)

In this problem,

Q=+757 kJ

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And the positive sign means the work is done BY the system.

5 0
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