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3 years ago

4. A weightlifter raises a mass mat a constant speed to a height h in time t. Which of the following

Physics

1 answer:

marishachu [46]3 years ago

3 0

Answer:

Explanation

The work done by the lifter is equal to its potential energy since he is covering a height and under the influence of gravity.

potential energy = mass * acceleration due to gravity * height

m is the mass

g is the acceleration due to gravity

h is the height

Hence the required workdone = PE = mgh

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A hammer taps on the end of a 4.10-m-long metal bar at room temperature. A microphone at the other end of the bar picks up two p

xz_007 [3.2K]

Answer:

Speed of sound inside metal is ≅ 8200 $\frac{m}{s}$

Explanation:

Given :

Length of metal bar $x = 4.10$ m

From general velocity equation,

$v = \frac{x}{t}$

Where $v =$ speed of sound in air = 343 $\frac{m}{s}$

For finding time from above equation,

$t = \frac{x}{v}$

$t = \frac{4}{343}$

$t = 0.01166$ sec

Since pulses are separated by $t_{o} =$ $11.1 \times 10^{-3} = 0.0111$ sec

So we take time difference,

$\Delta t = t_{} -t_{o} = 0.0005$

So speed of sound in metal is,

$v = \frac{x}{\Delta t }$

$v = \frac{4.10}{0.0005}$

$v = 8200$ $\frac{m}{s}$

4 0

3 years ago

One type of substance is a _________, which contains only one type of atom.

USPshnik [31]

One type of substance is a >>element<<, which contains only one type of atom.

3 0

4 years ago

Please help meeee

Mashutka [201]

Answer:

whichever teacher gave you this question is a legend

Explanation:

8 0

3 years ago

A missile is moving 1350 m/s at 25.0° angle. It needs to hit in a 55.0° direction in 10.20 s. What is the direction of its final

77julia77 [94]

Answer:

final velocity = 3504 m/s

Explanation:

Given data:

velocity of missile = Vi = 1350m/s

angle at which missile is moving = 25degree

distance between missile and targets = 23500m

angle between target and missile=55degree

time=10.2s

To find:

Final velocity: ?

Formula:

x = Vx*t + ½*ax*t²

Let x be the horizontal component of distance

x = ertical component of distance

t-time

ax = horizontal component of acceleration

ay = Vertical component of acceleration

Vx = horizontal component of velocity

Vy = Vertical component of velocity

Solution:

x = Vx*t + ½*ax*t²

23500m * cos55.0º = 1350m/s * cos25.0º * 10.20s + ½ * ax * (10.20s)²

ax = 19.2 m/s²

V'x = Vx + ax*t = 1350m/s * cos25.0º + 19.2m/s² * 10.20s = 1419 m/s

similarly vertically:

y = Vy*t + ½*ay*t²

23500m * sin55.0º = 1350m/s * sin25.0º * 10.20s + ½ * ay * (10.20s)²

ay = 258 m/s²

V'y = Vy + ay*t

= 1350m/s * sin25.0º + 258m/s² * 10.20s = 3204 m/s

V = √(V'x² + V'y²)

= 3504 m/s

8 0

3 years ago

Image formed in a concave

Hunter-Best [27]

Answer:

Explanation:

the image formed behind the mirrow= virtual

and the size of the image increase and upright

8 0

3 years ago