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3241004551 [841]
4 years ago
9

A pencil is rolled off a table of height 1.25 m. If it has a horizontal speed of 3.1 m/s, how long does it take the pencil to re

ach the ground? A. 0.51 s B. 1.12 s C. 0.40 s D. 2.48 s
Physics
1 answer:
Darya [45]4 years ago
7 0
The horizontal speed has no effect on how long it takes to reach the ground.
A bullet shot from a gun and a bullet dropped from the front end of the gun
at the same time as the shot both hit the ground at the same time.

The number that counts is the height from which it fell . . . the 1.25 m.

I'll use this very useful formula:

       Distance of free fall,
       starting from rest            = (1/2) · (gravity) · (time)²

                                  1.25 m  =  (1/2) · (9.8 m/s²) · (time)²

Divide each side
by   4.9 m/s²  :          1.25 m / 4.9 m/s²  =  time²

                                          0.2551 sec²  =  time²

Square root each side:       0.505 sec  =  time

It looks like the correct choice is approximately 'A'. (rounded)
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Answer:

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Explanation:

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3 years ago
A ball rolls with a speed of 2.0m/s across a level table that is 1.0m above the floor. Upon reaching the edge of the table it fo
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Answer:0.58 m

Explanation:

The initial velocity of the ball is u = 2.0 m/s

The height of the table is, h = 1.0 m

The ball falls in vertical direction under acceleration due to gravity.

Time taken for ball to hit the floor:

h= ut + 0.5gt² ( from the equation of motion)

1.0 m=2.0 m/s × t+0.5 × 9.8 m/s²× t²

Solving this for t,

t = 0.29 s ( we have neglected the negative value of t)

In the same time, the ball would cover a horizontal distance of :

s = u t

⇒s = 2.0 m/s×0.29 s = 0.58 m

Thus, the landing spot is 0.58 m away from the table.

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William WangHomework #33 Regents Review (3)0989Assignment Mode : Open (Time On Task) 9 of 25 ListenDuring a collision, an 84-kil
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Answer:

1.7\cdot 10^3 N

Explanation:

The impulse theorem states that the product between the force and the time interval of the collision is equal to the change in momentum:

F \Delta t = m \Delta v

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F is the force

\Delta t is the time interval

m is the mass

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m = 84 kg

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So we can solve the equation to find the force:

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