Physics, 15.11.2020 21:30 Emiann222

I need this type out answer question.

Answers: 2

Show answers

Answers

Answer from: bigmac34

The ball has 7.35 joules of energy at position B.

The velocity of the ball at position A is 3.13 meter/second

Explanation:

Kinetic and Gravitational Potential Energy

Kinetic energy is the form of energy that an object or a particle has by reason of its motion. An object of mass m and speed v has kinetic energy calculated by:

$\displaystyle K=\frac{1}{2}m.v^2$

Gravitational Potential Energy is the form of energy that an object has by reason of its height h relative to a certain reference. It can be calculated as follows:

U=m.g.h

Where g is the acceleration of gravity.

The figure shows a pendulum with a bob (ball) of mass m=1.5 Kg. When it's pulled to point B, it has a height of h= 0.5 m and set to rest.

The potential energy at that point is:

$U=1.5\ Kg\cdot 9.8 \ m/s^2\cdot 0.5\ m$

$U=7.35\ J$

The ball has 7.35 joules of energy at position B.

When the ball is released, all of the potential energy is transformed into kinetic energy when reaches point A. Thus:

K=7.35 J

From the equation of kinetic energy, we solve for v:

$\displaystyle v=\sqrt{\frac{2K}{m}}$

$\displaystyle v=\sqrt{\frac{2\cdot 7.35}{1.5}}$

$\displaystyle v=\sqrt{\frac{14.7}{1.5}}$

$\displaystyle v=\sqrt{9.8}$

v = 3.13 m/s

The velocity of the ball at position A is 3.13 meter/second

Answer from: Quest

force is mass*acceleration.

we have a very small mass: 11.4*0.001 kg

if we want 0.035n of force, we need an acceleration:

0.035 = 11.4*0.001*a

a = 0.035/(11.4*0.001) m/s^2

Answer from: Quest

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol

b. a hockey puck sliding across the ice

c. a compressed spring

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice is the correct option.