What is the momentum of a golf ball with a mass of 62 g moving at 73 m/s?

If an object is moving up, is it considered to have a positive or negative velocity?

grin007 [14]

Answer:

A positive velocity

Explanation:

7 0

3 years ago

A student in Denver (altitude = 1 mile = 1609 m above sea level) brings a physics book of mass 1.3 kg to the top of a ten story

Nesterboy [21]

Answer:

Explanation:

Potential energy is the energy of a body due to is virtue of rest.

Potential energy is given as mgh

g is a constant and it is 9.81m/s²

And also the mass of the body is given as 1.3kg

Now the height of the body is

He took a book to a storey building of height 26m

He still holds the book 151 cm (1.51m) above the house.

The house is on an altitude of 1609m from the sea level.

Total Ug with out the sea level is

Ug=mgh

Ug=1.3 × 9.81 ×(26+1.51)

Ug=350.84J

Then, the potential energy due to the sea level is given as

Ug=mgh

Where g = 1/6371 m/s²

Therefore

Ug=mgh

Ug=1.3 × 1/6371 ×1609

Ug=0.328J

Total energy = 0.328+350.84

Ug=351.17J

8 0

3 years ago

A catapult launches a test rocket vertically upward from a well, giving the rocket an initial speed of 80.6 m/s at ground level.

kow [346]

Before the engines fail, the rocket's altitude at time t is given by

$y_1(t)=\left(80.6\dfrac{\rm m}{\rm s}\right)t+\dfrac12\left(3.90\dfrac{\rm m}{\mathrm s^2}\right)t^2$

and its velocity is

$v_1(t)=80.6\dfrac{\rm m}{\rm s}+\left(3.90\dfrac{\rm m}{\mathrm s^2}\right)t$

The rocket then reaches an altitude of 1150 m at time t such that

$1150\,\mathrm m=\left(80.6\dfrac{\rm m}{\rm s}\right)t+\dfrac12\left(3.90\dfrac{\rm m}{\mathrm s^2}\right)t^2$

Solve for t to find this time to be

$t=11.2\,\mathrm s$

At this time, the rocket attains a velocity of

$v_1(11.2\,\mathrm s)=124\dfrac{\rm m}{\rm s}$

When it's in freefall, the rocket's altitude is given by

$y_2(t)=1150\,\mathrm m+\left(124\dfrac{\rm m}{\rm s}\right)t-\dfrac g2t^2$

where $g=9.80\frac{\rm m}{\mathrm s^2}$ is the acceleration due to gravity, and its velocity is

$v_2(t)=124\dfrac{\rm m}{\rm s}-gt$

(a) After the first 11.2 s of flight, the rocket is in the air for as long as it takes for $y_2(t)$ to reach 0:

$1150\,\mathrm m+\left(124\dfrac{\rm m}{\rm s}\right)t-\dfrac g2t^2=0\implies t=32.6\,\mathrm s$

So the rocket is in motion for a total of 11.2 s + 32.6 s = 43.4 s.

(b) Recall that

${v_f}^2-{v_i}^2=2a\Delta y$

where $v_f$ and $v_i$ denote final and initial velocities, respecitively, $a$ denotes acceleration, and $\Delta y$ the difference in altitudes over some time interval. At its maximum height, the rocket has zero velocity. After the engines fail, the rocket will keep moving upward for a little while before it starts to fall to the ground, which means $y_2$ will contain the information we need to find the maximum height.

$-\left(124\dfrac{\rm m}{\rm s}\right)^2=-2g(y_{\rm max}-1150\,\mathrm m)$

Solve for $y_{\rm max}$ and we find that the rocket reaches a maximum altitude of about 1930 m.

(c) In part (a), we found the time it takes for the rocket to hit the ground (relative to $y_2(t)$ ) to be about 32.6 s. Plug this into $v_2(t)$ to find the velocity before it crashes:

$v_2(32.6\,\mathrm s)=-196\frac{\rm m}{\rm s}$

That is, the rocket has a velocity of 196 m/s in the downward direction as it hits the ground.

3 0

3 years ago

A tennis player strikes a tennis ball from underneath with her racket. The ball is sent straight up with an initial velocity of

Stels [109]

So the acceleration of gravity is 9.8 m/s so that’s how quickly it will accelerate downwards. You can use a kinematic equation to determine your answer. We know that initial velocity was 19 m/s, final velocity must be 0 m/s because it’s at the very top, and the acceleration is -9.8 m/s. You can then use this equation:

Vf^2=Vo^2+2ax

Plugging in values:

361=19.6x

X=18 m

6 0

2 years ago

It takes at least 4 people to push a refrigerator up a 10-meter ramp. How many people would be needed to push the same refrigera

vaieri [72.5K]

Double the amount of people because the ramp went from 10-meter to 20-meter, so times by 2. 4 times 2 is 8.
The answer is 8 people.
Hope this helps!
Please give Brainliest!

8 0

1 year ago