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3 years ago

In a clock, the average speed is maximum for the tip of

Physics

2 answers:

seraphim [82]3 years ago

7 0

The answer is A) seconds hand

aleksandrvk [35]3 years ago

7 0

A) Seconds hand

There are 60 minutes in an hour, 1 hour in an hour, and 3,600 seconds in an hour. Since there are more seconds in an hour than minutes, the seconds hand moves at a much quicker rate than the other two hands.

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What was the direction of the ball’s velocity

Tju [1.3M]

Part of the question is missing. Here it is:

<em>A 72 g autographed baseball slides off of a 1.3 m high table and strikes the floor a horizontal distance of 0.7m away from the table. The acceleration of gravity is 9.81 m/s2. What was the direction of the ball’s velocity just before it hit the floor? </em>

Answer:

$\theta=-75.7^{\circ}$

Explanation:

The motion of the ball is a projectile motion, which consists of two separate motions:

- A horizontal motion at constant velocity

- A vertical motion at constant acceleration (free fall)

We start by analyzing the vertical motion, to find the time of flight of the ball. This can be done by using the suvat equation

$s=ut+\frac{1}{2}at^2$

where, choosing downward as positive direction:

s =1.3 m is the vertical displacement of the ball

u = 0 is the initial vertical velocity

$a=g=9.8 m/s^2$ is the acceleration of gravity

t is the time

Solving for t,

$t=\sqrt{\frac{2s}{a}}=\sqrt{\frac{2(1.3)}{9.8}}=0.52 s$

Now we can find the final vertical velocity of the ball, using:

$v_y=u+at$

And susbtituting t = 0.52 s, we find

$v_y = 0 +(9.8)(0.52)=5.1 m/s$

It is important to keep in mind that the direction of this velocity is downward, since we chose downward as positive direction.

The horizontal velocity of the ball instead is constant; we know that the ball covers a horizontal distance of

d = 0.7 m

In a time of

t = 0.52 s

So, the horizontal velocity is

$v_x = \frac{0.7}{0.52}=1.3 m/s$

So now we can find the direction of the ball's velocity using:

$\theta=tan^{-1}(\frac{v_y}{v_x})=tan^{-1}(\frac{5.1}{1.3})=75.7^{\circ}$

And since the vertical direction is downward, this means that this velocity is below the horizontal, so the answer is

$\theta=-75.7^{\circ}$

8 0

3 years ago

A student sees a newspaper ad for an apartment that has 2030 square feet (ft2) of floor space. How many square meters of area ar

Vilka [71]

Square feet or square meters?

8 0

3 years ago

When is acceleration positive, negative, and zero? Calculate the average speed if I walk to class at a speed of 20 meters/minute

Marrrta [24]

Part A: a->positive when velocity is increasing a->negative when velocity is decreasing a->zero when velocity is constant

6 0

3 years ago

A uniform magnetic field of magnitude 0.72 T is directed perpendicular to the plane of a rectangular loop having dimensions 8.2

Liono4ka [1.6K]

Answer:

Explanation:

Magnetic flux is expressed as the product of magnetic field and cross sectional area.

Φ = BAsintheta

Given

B = 0.72T

A = 8.2cm×14cm

A = 0.082m × 0.14m

Area = 0.01148m²

Theta = 90°

Substitute into the formula

Φ = BAsintheta

Φ = 0.72(0.01148)sin90°

Φ = 0.72(0.01148)(1)

Φ = 0.0082656

Hence the magnetic flux through the loop is 8.2656 × 10^-3 Weber

8 0

3 years ago

An object at a distance of 6400km from the centre

Fittoniya [83]

Answer:

12.5N

Explanation:

From newton law of universal gravitation F= GmM/d2.

that means Force is inversely proportional to the square of the distance apart.

F1= 50N, d1=6400km

F2=?, d2=12800km

F1/F2=d2×d2/d1×d1 so we have 50/F2= 12800×12800/6400×6400...F2=6400×6400×50/(12800×12800)=12.5N

6 0

3 years ago