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4 years ago

Why is the answer B and not E?

Physics

2 answers:

makkiz [27]4 years ago

8 0

Answer: B

Explanation:

E shows the direction of the ball but the question asks about the direction of the STICK, which is the opposite of the ball.

Margarita [4]4 years ago

5 0

Explanation:

The ball's horizontal velocity changes from vi to 0, so the acceleration is negative, meaning the force component must point to the left.

The ball's vertical velocity changes from 0 to vf, so the acceleration is positive, meaning the force component must point up.

So you're looking for a force that points to the left and up, where the horizontal component is greater than the vertical component.

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A train moves from rest to a speed at 25m/s in 30.0 seconds. What is it’s acceleration?

sasho [114]

Answer:

25/30 = 5/6 m/s^2 5/6 meters per second squared

4 0

3 years ago

A 200kg ball on the end of string is swung in horizontal circle with radius of 0.5m . The ball makes revolution every 2second th

ANEK [815]

Answer: $\dfrac{\pi}{2} ms^{-1}$

Explanation:

Let $T$ be the time required to make one revolution.

Let $r$ be the radius of the circular path.

Let $d$ be the distance travelled by ball in one revolution.

As we know,the distance travelled in one revolution is the circumference of the circle.

So, $d=2\pi r$

Given, $d=0.5m\\T=2sec$

$d=2\times \pi \times 0.5=\pi m$

Speed of an object moving is circular path is define as the ratio of distance travelled in one revolution to the time taken by the object to complete one revolution.

Let $s$ be the speed of the ball.

$s=\frac{d}{T}=\frac{\pi }{2}ms^{-1}$

So,the speed of the ball is $\frac{\pi }{2}ms^{-1}$

5 0

3 years ago

Jill can use a force of 12.0 N to lift a single box up 5.00 m. How many of these boxes must she lift it in a minute to use 60.0

Mama L [17]

Answer:

60 boxes

Explanation:

The work done by lifting a single box is equal to the force applied (the weight of the box) times the displacement of the box:

$W_1 = Fd=(12.0 N)(5.00 m)=60 J$

Power is related to the work done by the equation:

$P=\frac{W}{t}$

where W is the work done and t is the time. In this problem, we are told that the power used is P=60.0 W, while the time taken is t = 1 min = 60 s, so the total work done must be

$W=Pt=(60.0 W)(60 s)=3600 J$