All categories

4 years ago

¿Qué energía cinética posee una pelota de tenis de 65 g que se sirve a una velocidad de 200 km / h?

1 answer:

4 0

Therefore, the kinetic energy of an object is proportional to the square of its velocity (speed). In other words, If there is a twofold increase in speed, the kinetic energy will increase by a factor of four. If there is a threefold increase in speed, the kinetic energy will increase by a factor of nine.

You might be interested in

A grocery shopper tosses a(n) 9.0 kg bag of rice into a stationary 17.4 kg grocery cart. The bag hits the cart with a horizontal

noname [10]

Answer:

$V=1.77m/s$

Explanation:

#Using the conservation of momentum , momentum before equals momentum after( $p=mv)$ .

-Initial speed is 5.2m/s while the cart is at rest. After, the velocity will be of a combined(bag+cart) mass.

Hence:

$9.0\times 5.2+17.4\times 0=(9+17.4)V\\\\V=\frac{9\times5.2}{9+17.4}\\\\=1.77m/s\\$

Hence, the final velocity of the cart and bag is 1.77m/s

7 0

4 years ago

1. An electron (Q=16x10^-20 C, m=1x10^-30 kg) moving at half a megameter per second up the page enters a region with a uniform m

jek_recluse [69]

Explanation:

It is given that,

Charge on electron, $q=16\times 10^{-20}\ C$

Mass of the electron, $m=9.1\times 10^{-31}\ kg$

Speed of the electron, $v=0.5\ Mm/s=0.5\times 10^6\ m/s$

Magnetic field, B = 1 T (directed out of the page)

Let F is the magnetic force acting on the electron. It is given by :

$F=qvB\ sin\theta$

Here, $\theta=90^{\circ}$

$F=qvB$

$F=16\times 10^{-20}\ C\times 0.5\times 10^6\ m/s\times 1\ T$

$F=8\times 10^{-14}\ N$

Using the right hand rule, the direction of magnetic force is upward to the plane of the paper. Also, the electron will follow the circular path. It is given by :

$r=\dfrac{mv}{qB}$

$r=\dfrac{9.1\times 10^{-31}\ kg\times 0.5\times 10^6\ m/s}{16\times 10^{-20}\ C\times 1\ T}$

$r=2.84\times 10^{-6}\ m$

Hence, this is the required solution.

7 0

3 years ago

An electromagnetic wave in a vacuum has a wavelength of 0.032 m. What is its frequency?

Sergio [31]

L=wavelength
L=0.032
c=Lf
f=c/L
f=3e8/0.032
f=9.375GHz

7 0

3 years ago

3. Two cyclists that are 500 m apart start biking toward each other. They bike at speeds of 6 and

Veronika [31]

Answer:

A) 50 seconds

B) 200 m

Explanation:

They are 500 metres apart.

And one of the bike loves at 6 m/s while the other loves at 4 m/s.

A) Let distance of the 6 m/s bike before they meet be x.

Thus, time = x/6

Since time = distance/speed

For the second bike at 4 m/s, his distance covered before they meet will be 500 - x

Thus, time = (500 - x)/4

Now they will meet each other at the same time. Thus;

x/6 = (500 - x)/4

Cross multiply to get;

4x = 3000 - 6x

6x + 4x = 3000

10x = 3000

x = 3000/10

x = 300 m

Thus, time will be;

t = 300/6

t = 50 seconds

B) Distance covered by the slower bike is (500 - x)

Since from a above, x = 300

Thus; distance = 500 - 300 = 200 m

4 0

3 years ago

A warm hockey puck has a coefficient of restitution of 0.50, while a frozen hockey puck has a coefficient of restitution of only

AlexFokin [52]

Answer:

the required height is 0.2449 m only

Explanation:

Given the data in the question;

Initial height = 2m

so speed of the puck before hitting the ground will be;

u² = 2gh

Initial speed u_ball = √2gh

u_ball = √( 2 × 9.8 × 2 )

u_ball = √39.2

u_ball = 6.26 m/s

given that; FOR THE FROZEN PUCK, coefficient of restitution = 0.35 only

R = - (v_ball - v_ground / u_ball - u_ ground)

0.35 = - (v_ball - 0 / 6.26 - 0)

0.35 = -v_ball / - 6.26

-v_ball = 0.35 × (- 6.26)

-v_ball = -2.191 m/s

v_ball = 2.191 m/s

to get the height;

v² = 2gh

h = v² / 2g

we substitute

h = (2.191)² / 2×9.8

h = 4.800481 / 19.6

h = 0.2449 m

Therefore, the required height is 0.2449 m only

5 0

3 years ago