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3 years ago

A weightlifter presses a 400 n weight 0.5 m over his head in 2 seconds, what is the power of the weight lifter

1 answer:

3 0

There are two ways to solve this problem. First we write the given.

Given: Force F = 400 N; Height h = 0.5 m; Time t = 2 s

Formula: P = W/t; but Work W = Force x distance or W = f x d

Weight is also a Force, therefore: W = mg, solve for Mass m = ?

m = w/g m = 400 N/9.8 m/s² m = 40.82 Kg

P = W/t = F x d/t = mgh/t P = (40.82 Kg)(9.8 m/s²)/2 s

P = 100 J/s or 100 Watts

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A man walks 30 m to the west than 5 m to the east in 45 seconds.

harkovskaia [24]

Answer:

35 m

0.56 m/s west

Explanation:

A) Total distance is the length of the path taken.

30 m + 5 m = 35 m

B) Velocity is displacement over time. Displacement is the difference between the final position and the initial position.

If west is -x, and east is +x, then:

Δx = -30 m + 5 m

Δx = -25 m

v = Δx / t

v = -25 m / 45 s

v = -0.56 m/s

v = 0.56 m/s west

4 0

3 years ago

What is kinetic energy

Elena L [17]

Answer:

energy which a body possesses by virtue of being in motion.

Explanation:

7 0

4 years ago

Steam enters a one-inlet, two-exit control volume at location (1) at 360°C, 100 bar, with a mass flow rate of 2 kg/s. The inlet

yaroslaw [1]

Answer:

The inlet velocity is 21.9 m/s.

The mass flow rate at reach exit is 1.7 kg/s.

Explanation:

Given that,

Mass flow rate = 2 kg/s

Diameter of inlet pipe = 5.2 cm

Fifteen percent of the flow leaves through location (2) and the remainder leaves at (3)

The mass flow rate is

$m_{2}=0.15\times2$

We need to calculate the mass flow rate at reach exit

Using formula of mass

$m_{3}=m_{1}-m_{2}$

$m_{3}=2-0.15\times2$

$m_{3}=1.7\ kg/s$

We need to calculate the inlet velocity

Using formula of velocity

$v=\dfrac{m}{\rho A}$

Put the value into the formula

$v=\dfrac{2}{42.868\times\dfrac{\pi}{4}\times(5.2\times10^{-2})^2}$

$v=21.9\ m/s$

Hence, The inlet velocity is 21.9 m/s.

The mass flow rate at reach exit is 1.7 kg/s.

7 0

4 years ago

The speed of sound in wood is ____ the speed of sound in water.

pishuonlain [190]

Answer:

greater

Explanation:

the speed of sound in steel is greater than water. the speed of sound in wood is not, In water, the particles are much closer together, and they can quickly transmit vibration energy from one particle to the next. This means that the sound wave travels over four times faster than it would in air, but it takes a lot of energy to start the vibration.

Wood is less dense and force can make a sound.

8 0

3 years ago

A block of mass m = 1.00 kg is attached to a spring of force constant k = 500 N/m. The block is pulled to a position xi= 5.00 cm

8_murik_8 [283]

Answer:

The speed of the block is 4.96 m/s.

Explanation:

Given that.

Mass of block = 1.00 kg

Spring constant = 500 N/m

Position $x_{i}=5.00\ cm$