All categories

4 years ago

An object has 90,000 J of kinetic energy and is moving at 12 m/s. What is the objects mass?

Physics

1 answer:

trapecia [35]4 years ago

4 0

Answer:

plug it into your calculator

Explanation:

Kinetic energy = KE = Joules = J

KE= 1/2mv^2

90,000 = 1/2 m (12^2)

180,000 = m (144)

m = 180,000 / 144

You might be interested in

A car owner forgets to turn off the headlights of his car while it is parked in his garage. If the 12.0-V battery in his car is

avanturin [10]

Answer: 22.6 hours

Explanation:

The power is the measure of the rate of energy.

In this problem, the 12.0 V battery is rated at 51.0 Ah, which means it delivers 51.0 A of current in a time of t = 1 h = 3600 s. The power delivered by the battery can be written as

$P=IV$

where

I is the current

V = 12.0 V is the voltage of the battery

So the energy delivered by the battery can be written as

$E=Pt=VIt$

Where

$It=51.0 A\cdot h = 51.0 A \cdot 3600 s/h=183,600 A\cdot s$

So the energy delivered is

$E=(12.0)(183,600)=2.2\cdot 10^6 J$

At the same time, the headlight consumes 27.0 W of power, so 27 Joules of energy per second; Therefore, it will remain on for a time of:

$t=\frac{2.2\cdot 10^6 J}{27.0 W}=81481 s = 22.6 h$

3 0

3 years ago

Pancake syrup taken out of the refrigerator will be difficult to pour because low temperature increases viscosity.

DiKsa [7]

<span>Pancake syrup taken out of the refrigerator will be difficult to pour because low temperature increases viscosity.

a)True

</span>

4 0

3 years ago

Read 2 more answers

(a) What is the vapor pressure of water at 20.0ºC ? (b) What percentage of atmospheric pressure does this correspond to? (c) Wha

DENIUS [597]

Answer:

a). Vapour pressure = 2333.141 Pa

b). Percentage of atmospheric pressure = 99 %

c). Percentage of water vapour = 1.4 %

Explanation:

a). From water saturation pressure table,

Vapour pressure of water at 20°C is 17.5 torr

We know, 1 torr = 133.322 Pa

Therefore, 17.5 torr = 2333.141 Pa

Therefore, vapour pressure at 20°C is 2333.141 Pa

b). At 20°C, the pressure at atmospheric unit = 0.0231 atm

= 0.0231 x $10^{5}$ Pa

= 2310 Pa

Therefore, $\frac{2310}{2333.141}$

= 0.99

Therefore percentage of atmospheric pressure = 0.99 x 100

= 99 %

c). We Know

Relative Humidity (Rh)= $\frac{P_{v}}{P_{saturation}}$

where $P_{v}$ is vapour pressure

Rh is given as 100% = 1

∴ 1 = $\frac{P_{v}}{P_{saturation}}$

$P_{v}=P_{saturation}$ = 2333.141 Pa

Now humidity ratio is

$w = \frac{m_{v}}{m_{a}}$ , where $m_{v}$ is mass of vapour

$m_{a}$ is mass of air

$w = 0.622\times \frac{P_{v}}{P_{total}-P_{v}}$

Let the total pressure be $10^{5}$ Pa

$w = 0.622\times \frac{2333.141}{10^{5}-2333.141}$

$w = 0.01485$

Therefore, percentage of water vapour is 0.01485 x 100

= 1.4 %

8 0

3 years ago

You are sitting on a deck of your house surrounded by oak trees. You hear the sound of an acorn hitting the deck. You wonder if

Black_prince [1.1K]

Answer: 96N

Explanation:

To calculate the velocity of the impact On the persons head, we have

h = gt²/2

14 = 9.81t²/2

t² = 28/9.8

t² = 2.86

t = 1.69s

V = u + at

V = 0 + 9.81*1.69

V = 16.58m/s

a(average) = (v1² + v2²) /2Δy

a(average) = 16.58² + 0)/2 * 0.005

a(average) = 274.8964/0.01

a(average) = 27489.64m/s²

Using newton's second law of motion,

F(average) = m * a(average)

F(average) = 0.0035 * 27489.64

F(average) = 96.21N

Therefore the force needed by the acorn to do much damage starts from 96N

8 0

3 years ago

Two people start biking from the same point. One bikes east at 9 mph, the other south at 28 mph. What is the rate at which the d

Irina-Kira [14]

Answer:

(a) 31.75 mph

(b) 31.77 mph

Explanation:

(a) For t = 10 min = 10 / 60 = 1 / 6 hour

According to the question,

dx /dt = 15 mph

dy / dt = 28 mph

After 10 minutes

x = 1/6 x 15 = 2.5 miles

y = 1/6 x 28 = 4.67 miles

$d = \sqrt{x^{2}+y^{2}}=\sqrt{2.5^{2}+4.67^{2}} = 5.3 miles$

According to diagram

$D^{2} = {x^{2}+y^{2}}$

Differentiate both sides with respect to t.

2D dD/dt = 2 x dx/dt + 2y dy/dt

D dD/dt = x dx/dt + y dy/dt

5.3 dD/dt = 2.5 (15) + 4.67 (28)

dD/dt = 31.75 miles/hour

(b) For t = 55 minutes = 55 / 60 hours

After 55 / 60 hours

x = 55 / 60 (15) = 13.75 miles

y = 55 / 60 (28) = 25.67 miles

$d = \sqrt{x^{2}+y^{2}}=\sqrt{13.75^{2}+25.67^{2}} = 29.12 miles$

According to diagram

$D^{2} = {x^{2}+y^{2}}$

Differentiate both sides with respect to t.

2D dD/dt = 2 x dx/dt + 2y dy/dt

D dD/dt = x dx/dt + y dy/dt

29.12 dD/dt = 13.75 (15) + 25.67 (28)

dD/dt = 31.77 miles/hour

8 0

4 years ago