All categories

3 years ago

Two boxers are fighting. Boxer 1 throws his 5 kg fist at boxer 2 with a speed of 9 m/s.

Physics

1 answer:

Sladkaya [172]3 years ago

4 0

Answer:

0.001 s

Explanation:

The force applied on an object is equal to the rate of change of momentum of the object:

$F=\frac{\Delta p}{\Delta t}$

where

F is the force applied

$\Delta p$ is the change in momentum

$\Delta t$ is the time interval

The change in momentum can be written as

$\Delta p=m(v-u)$

where

m is the mass

v is the final velocity

u is the initial velocity

So the original equation can be written as

$F=\frac{m(v-u)}{\Delta t}$

In this problem:

m = 5 kg is the mass of the fist

u = 9 m/s is the initial velocity

v = 0 is the final velocity

F = -45,000 N is the force applied (negative because its direction is opposite to the motion)

Therefore, we can re-arrange the equation to solve for the time:

$\Delta t=\frac{m(v-u)}{F}=\frac{(5)(0-9)}{-45,000}=0.001 s$

You might be interested in

An infinitely long straight wire has a uniform linear charge density of Derive the 4. equation for the electric field a distance

marshall27 [118]

Answer:

$E = \frac{\lambda}{2\pi \epsilon_0 r}$

Explanation:

Let the linear charge density of the charged wire is given as

$\frac{q}{L} = \lambda$

here we can use Gauss law to find the electric field at a distance r from wire

so here we will assume a Gaussian surface of cylinder shape around the wire

so we have

$\int E. dA = \frac{q}{\epsilon_0}$

here we have

$E \int dA = \frac{\lambda L}{\epsilon_0}$

$E. 2\pi r L = \frac{\lambda L}{\epsilon_0}$

so we have

$E = \frac{\lambda}{2\pi \epsilon_0 r}$

4 0

3 years ago

two metal plates are near each other. explain why they will not become charged until connected to a souce of potential differenc

scZoUnD [109]

Answer:

idk

Explanation:

7 0

3 years ago

How much of the electromagnetic spectrum is visible light?

Margarita [4]

I believe the answer is D, only a small part of it

8 0

3 years ago

Read 2 more answers

Two cylinders A&B at the same temperature contains the same quantity of the same kind of gas. Cylinder A has three times the

GREYUIT [131]

Answer:

pressure in cylinder A must be one third of pressure in cylinder B

Explanation:

We are told that the temperature and quantity of the gases in the 2 cylinders are same.

Thus, number of moles and temperature will be the same for both cylinders.

To this effect we will use the formula for ideal gas equation which is;

PV = nRT

Where;

P is prrssure

V is volume

n is number of moles

T is temperature

R is gas constant

We are told that Cylinder A has three times the volume of cylinder .

Thus;

V_a = 3V_b

For cylinder A;

Pressure = P_a

Volume = 3V_b

Number of moles = n

Thus;

P_a × 3V_b = nRT

For cylinder B;

Pressure = P_b

Volume = V_b

Number of moles = n

Thus,

P_b × V_b = nRT

Combining the equations for both cylinders, we have;

P_a × 3V_b = P_b × V_b

V_b will cancel out to give;

3P_a = P_b

Divide both sides by 3 to get;

P_a = ⅓P_b

Thus, pressure in cylinder A must be one third of pressure in cylinder B

3 0

3 years ago

A 3-kW resistance heater in a water heater runs for 3 hours to raise the water temperature to the desired level. Determine the a

Kipish [7]

Answer:

Energy, 9 kWh or 32400 kJ

Explanation:

Given that,

The power of heater, P = 3 kW

It runs for 3 hours to raise the water temperature to the desired level. We need to find the amount of electric energy used. We know that the electrical power of an object is given by total energy delivered per unit time. It is given by :

$P=\dfrac{E}{t}$

$E=P\times t$

$E=3\ kW\times 3\ h$

E = 9 kWh

Since, 1 kWh = 3600 kJ

E = 32400 kJ

So, the amount of electric energy used is 9 kWh or 32400 kJ. Hence, this is the required solution.

4 0

3 years ago