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2 years ago

A 60 kg man jumps down from a 0.8 m table. What is the speed when he

Physics

1 answer:

Rom4ik [11]2 years ago

4 0

Answer: Speed = 4 m/s

Explanation:

The parameters given are

Mass M = 60 kg

Height h = 0.8 m

Acceleration due to gravity g= 10 m/s2

Before the man jumps, he will be experiencing potential energy at the top of the table.

P.E = mgh

Substitute all the parameters into the formula

P.E = 60 × 9.8 × 0.8

P.E = 470.4 J

As he jumped from the table and hit the ground, the whole P.E will be converted to kinetic energy according to conservative of energy.

When hitting the ground,

K.E = P.E

Where K.E = 1/2mv^2

Substitute m and 470.4 into the formula

470.4 = 1/2 × 60 × V^2

V^2 = 470.4/30

V^2 = 15.68

V = square root (15.68)

V = 3.959 m/s

Therefore, the speed of the man when hitting the ground is approximately 4 m/s

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Kieran takes off from rest down a 50 m high, 10° slope on his jet-powered skis. The skis have a thrust of 280 N parallel to the

xz_007 [3.2K]

Answer:0.46

Explanation:

Given

Initial height $h=50 m$

inclination $\theta =10^{\circ}$

Thrust $=280 N$

combined mass of kieran and skis $m=50 kg$

Speed at the bottom $v=40 m/s$

From Work Energy Theorem

Work done by all the force is equal to change in kinetic Energy

$W_{gravity}+W_{friction}+W_{thrust}=\frac{1}{2}mv^2-0$ ------------1

distance traveled along the slope $x=\frac{50}{\sin 10}=287.93 m$

$W_{gravity}=mgh=50\times 9.8\times 50=24500 J$

$W_{thrust}=F\times x=280\times 287.93=80,620.4 J$

$W_{friction}=-\mu mg\cos 10$

substitute in 1

$24,500+80,620.4+W_{friction}=\frac{1}{2}\times 50\times 1600$

$W_{friction}=40,000-24,500-80,620.4$

$-\mu \cdot 50\times 9.8\times 287.93=-65,120.4$

$\mu =\frac{65,120.4}{141,085.7}=0.46$

8 0

2 years ago

Consider a keen little boy who is having a wagon race with a friend. He starts from rest and

MAXImum [283]

A) His wagon will accelerate more.
B) His wagon will accelerate less. Both parts are answered by F=ma. Mass is inversely proportional to acceleration, and force is directly proportional to acceleration.

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2 years ago

When an electric current flows through a long conductor, each free electron moves

nirvana33 [79]

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3 years ago

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5. A group of at

Sveta_85 [38]

Answer:

A group of atoms where the magnetic fields of the atoms point in the same direction is a magnetic domain.

Explanation:

In every magnet's magnetic field there is a region where the magnetization is in the same direction. This region is known as magnetic domain.
In the magnetic domain the atoms always points in the same magnetic filed direction.
All the atom's magnetic field align in one particular direction.
This region where atoms align is called as domains.

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2 years ago

A stunt man jumps from the top of a building and lands 10 meters below his initial height. In case A, the stunt man lands on a s

krek1111 [17]

Answer:

Explanation:

The stunt will likely sustain serious injury in case of concrete blocks because the average force acting on the person will be more because concrete blocks do not squeeze to provide more time for the force to act on the body instead it acts for a small amount of interval.

$Impulse=F_{avg}\times \Delta T$

As impulse is constant so time requires to act force on the body is more as compared to concrete block and thus average force in mattress case is less.

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3 years ago