All categories

3 years ago

If the velocity of a runner changes from -2 m/s to -4 m/s over a period of time, the

Physics

1 answer:

Mnenie [13.5K]3 years ago

3 0

Answer:

It will be A. So since its 2 times more the kinetic energy. But then you have to square it 2^2 = 4

You might be interested in

The kitchen in your house measures 10 ft by 10 ft. You need to have 50 footcandles of illumination in the room. How many 60 watt

tekilochka [14]

Answer:

<u>6 bulbs</u> are needed to illuminate the room.

Explanation:

Given:

Measurement of kitchen (A) = 10 ft by 10 ft = 100 sq. ft

Number of footcandles (n) = 50

Lumens emitted by 1 bulb = 834

Number of bulbs (N) = ?

We are also given,

1 foot candle = 1 lumen/sq. ft

So, 50 foot candles = 50 lumens/sq. ft

Now, for an area of 1 sq. ft 50 lumens are emitted.

So, for an area of 100 sq. ft, lumens emitted = 50 × 100 = 5000 lumens

Now, one bulb emits = 834 lumes

Therefore, number of bulbs required for emitting 5000 lumens is given as:

$N=\frac{Number\ of\ lumens}{Number\ of\ lumens\ by\ 1\ bulb}\\\\N=\frac{5000}{834}=5.995\approx6$

So, 6 bulbs are needed to illuminate the room.

7 0

3 years ago

If you can throw a stone straight up to height h, what’s the maximum horizontal distance you could throw it over level ground?

Mariana [72]

To answer this question, first we take note that the maximum height that can be reached by an object thrown straight up at a certain speed is calculated through the equation,
Hmax = v²sin²θ/2g
where v is the velocity, θ is the angle (in this case, 90°) and g is the gravitational constant. Since all are known except for v, we can then solve for v whichi s the initial velocity of the projectile.

Once we have the value of v, we multiply this by the total time traveled by the projectile to solve for the value of the range (that is the total horizontal distance).

8 0

3 years ago

Read 2 more answers

Could I please get some help on this question I don’t understand .

Oksana_A [137]

Answer:

12.5 m/s

Explanation:

From the question given above, the following data were obtained:

Initial velocity (u) = 0 m/s

Height (h) = 8 m

Final velocity (v) at 8 m above the lowest point =?

NOTE: Acceleration due to gravity (g) = 9.8 m/s²

The velocity of the roller coaster at 8 m above the lowest point can be obtained as follow:

v² = u² + 2gh

v² = 0² + (2 × 9.8 × 8)

v² = 0 + 156.8

v² = 156.8

Take the square root of both side

v = √156.8

v = 12.5 m/s

Therefore, the velocity of the roller coaster at 8 m above the lowest point is 12.5 m/s.

5 0

3 years ago

A 12.0-g bullet is fi red horizontally into a 100-g wooden block initially at rest on a horizontal surface. After impact, the bl

allochka39001 [22]

Answer:

$v_1 = 91.3 m/s$

Explanation:

By energy conservation and work energy theorem we can say that after bullet hits the block, it will move on the rough floor and comes to rest

so here work done by frictional force = change in kinetic energy

so we know that

$W_f = \frac{1}{2}mv_f^2 - \frac{1}{2}mv_i^2$

$-\mu mg d = \frac{1}{2}m(v_f^2 - v_i^2)$

$-0.650(9.81)(7.5) = \frac{1}{2}(0 - v_i^2)$

$47.8 = \frac{1}{2}v^2$

$v = 9.78 m/s$

now by momentum conservation we have

$m_1 v_1 = (m_1 + m_2) v$

$12 v_1 = (100 + 12) 9.78$

$v_1 = 91.3 m/s$

3 0

3 years ago

the large,flat piece of wood within a piano serves the same purpose as(a)a bamboo reed(b)a set of wooden drum sticks(c)a guitar

sammy [17]

The correct answer for the question that is being presented above is this one: "(d) the hollow bix." The large, flat piece of wood within a piano serves the same purpose as <span>(d) the hollow bix. The piece of flat wood will help piano produce a good quality sound.</span>

4 0

3 years ago

Read 2 more answers