The bicyclist accelerates with magnitude <em>a</em> such that
25.0 m = 1/2 <em>a</em> (4.90 s)²
Solve for <em>a</em> :
<em>a</em> = (25.0 m) / (1/2 (4.90 s)²) ≈ 2.08 m/s²
Then her final speed is <em>v</em> such that
<em>v</em> ² - 0² = 2<em>a</em> (25.0 m)
Solve for <em>v</em> :
<em>v</em> = √(2 (2.08 m/s²) / (25.0 m)) ≈ 10.2 m/s
Convert to mph. If you know that 1 m ≈ 3.28 ft, then
(10.2 m/s) • (3.28 ft/m) • (1/5280 mi/ft) • (3600 s/h) ≈ 22.8 mi/h
Set up the problem with the conversion rates as fractions where when you multiply the units cancel out leaving the desired units behind.
I think the answer is A because it’s a better explanation
Answer:
Impulse, |J| = 0.6716 kg-m/s
Force, F = 63.35 N
Explanation:
It is given that,
Mass of the baseball, m = 0.146 kg
Initial speed of the ball, u = 15.3 m/s
Final speed of the ball, v = 10.7 m/s
To find,
(a) The magnitude of this impulse.
(b) The magnitude of the average force of the glass on the ball.
Solution,
(a) Impulse of an object is equal to the change in its momentum. It is given by :


J = -0.6716 kg-m/s
or
|J| = 0.6716 kg-m/s
(b) Another definition of impulse is given by the product of force and time of contact.
t = 0.0106 s



F = 63.35 N
Hence, this is the required solution.