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3 years ago

15

help! im timed. A ball is thrown downward with an initial velocity of 12.1 m/s. How long will it take to reach a velocity of -24

.5 m/s?

1 answer:

Ulleksa [173]3 years ago

4 0

Answer:

$1.27\:\text{s}$

Explanation:

We can use the following kinematics equation to solve this problem:

$v_f=v_i+at$

Solving for $t$ :

$-24.5=-12.1+-9.8t,\\-12.4=-9.8t,\\t=\frac{-12.4}{-9.8}\approx \boxed{1.27\:\mathrm{s}}$

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3 years ago

Charge q is 1 unit of distance away from the source charge S. Charge p is two times further away. The force exerted between S an

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Answer : The correct option is, (d) 4 times

Solution :

According to the Coulomb's law, the electrostatic force of attraction or repulsion between two charges is directly proportional to the product of the charges and is inversely proportional to the square of the distance between the the charges.

Formula used :

$F=k_e\frac{q_1q_2}{r^2}$

where,

F = electrostatic force of attraction or repulsion

$k_e$ = Coulomb's constant

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First we have to calculate the force exerted between S and q when the distance between the charge is 1 unit and let us assumed that the charge be 'q'

$F_{sq}=k_e\frac{qq}{1^2}=k_e\times q^2$ ..........(1)

Now we have to calculate the force exerted between S and p when the distance between the charge is 2 unit at the same charge.

$F_{sp}=k_e\frac{qq}{2^2}=k_e\frac{q^2}{4}$ ...........(2)

Equation equation 1 and 2, we get

$\frac{F_{sq}}{F_{sp}}=\frac{1}{4}$

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Therefore, the force exerted between S and q is 4 times the force exerted between S and p.

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3 years ago

Read 2 more answers

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Answer:

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4 years ago

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3 years ago

A striped billiard ball moves toward the right with speed 3 m/s. A solid billiard ball with the same mass moves toward the left

Helen [10]

Answer:

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Explanation:

Given :

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Putting value of u from equation 2 to equation 1 .

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And , u = -3 m/s .

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4 years ago