Ask question

Ask question

All categories

3 years ago

11

A firework is initially at rest explodes into 2 pieces one of which weighing 2.0 kg flies to the right at15 m/s the other piece

flies to tje left at 20m/s wjat is tge mass of firework before explosion??

1 answer:

sergiy2304 [10]3 years ago

5 0

Answer:

3.5 kg

Explanation:

Momentum is conserved.

Mu = m₁v₁ + m₂v₂

0 = (2.0 kg) (15 m/s) + m (-20 m/s)

m = 1.5 kg

M = m + 2.0 kg

M = 3.5 kg

You might be interested in

A hunter fires a rifle while seated with the butt of the gun resting against their shoulder. If the forward momentum is the same

Debora [2.8K]

Answer:

Because the bullet is smaller and has a sharp/pointy tip.

Explanation:

The bullet kinda puts the majority of kinetic energy in a small are, whereas the gun butt kinda spreads the energy evenly amongst a larger surface. If more explanation is needed add comment.

6 0

3 years ago

A rock is thrown upward from a bridge into a river below. The function f(t)=−16t2+44t+88 determines the height of the rock above

babymother [125]

1) 88 ft

2) 4.09 s

3) 1.38 s

4) 118.2 m

Explanation:

1)

For an object thrown upward and subjected to free fall, the height of the object at any time t is given by the suvat equation:

$h(t) = h_0 + ut - \frac{1}{2}gt^2$ (1)

where

$h_0$ is the height at time t = 0

$u$ is the initial vertical velocity

$g=32 ft/s^2$ is the acceleration due to gravity

The function that describes the height of the rock above the surface at a time t in this problem is

$f(t)=-16t^2+44t+88$ (2)

By comparing the terms with same degree of eq(1) and eq(2), we observe that

$h_0 = 88 ft$

which means that the rock is at height h = 88 ft when t = 0: therefore, this means that the height of the bridge above the water is 88 feet.

2)

The rock will hit the water when its height becomes zero, so when

$f(t)=0$

which means when

$0=-16t^2+44t+88$

First of all, we can simplify the equation by dividing each term by 4:

$0=-4t^2+11t+22$

This is a second-order equation, so we solve it using the usual formula and we find:

$t_{1,2}=\frac{-b \pm \sqrt{b^2-4ac}}{2a}=\frac{-11\pm \sqrt{(11)^2-4(-4)(22)}}{2(-4)}=\frac{-11\pm \sqrt{121+352}}{-8}=\frac{-11\pm 21.75}{-8}$

Which gives only one positive solution (we neglect the negative solution since it has no physical meaning):

t = 4.09 s

So, the rock hits the water after 4.09 seconds.

3)

Here we want to find how many seconds after being thrown does the rock reach its maximum height above the water.

For an object in free fall motion, the vertical velocity is given by the expression

$v=u-gt$

where

u is the initial velocity

g is the acceleration due to gravity

t is the time

The object reaches its maximum height when its velocity changes direction, so when the vertical velocity is zero:

$v=0$

which means

$0=u-gt$

Here we have

$u=+44 ft/s$ (initial velocity)

$g=32 ft/s^2$ (acceleration due to gravity)

Solving for t, we find the time at which this occurs:

$t=\frac{u}{g}=\frac{44}{32}=1.38 s$

4)

The maximum height of the rock can be calculated by evaluating f(t) at the time the rock reaches the maximum height, so when

t = 1.38 s

The expression that gives the height of the rock at time t is

$f(t)=-16t^2+44t+88$

Substituting t = 1.38 s, we find:

$f(1.38)=-16(1.38)^2 + 44(1.38)+88=118.2 m$

So, the maximum height reached by the rock during its motion is

$h_{max}=118.2 m$

Which means 118.2 m above the water.

3 0

4 years ago

Complete this sentence. The solubility of a sample with ______ when the size of the sample increases

jeka57 [31]

stays the same

please mark as brainliest <3

6 0

3 years ago

Brainliest..... plz help!!!!!!!!!

alisha [4.7K]

Tamam hocam nasılsınız hocam proje konularını atabilirmisiniz ne kadar çok seviyorum çok öpüyorum iyi akşamlar yarın görüşürüz iyi geceler Allah rahatlık var bir şey var ya bir insan değilim ki bir şey olmaz sen kaç gibi müsait olur musun lütfen bana yardımcı olabilir misin bir insan bir

4 0

3 years ago

A piece of taffy slams into and sticks to another identical piece of taffy that is at rest. The momentum of the two pieces stuck

Yanka [14]

Answer:0.5

Explanation:

Given

Piece of taffy slams in to sticks to another identical piece and stuck into it.

Let m be the mass of taffy and u be the initial velocity of taffy and v be the final velocity of system.

Conserving momentum

$mu=2mv$

$v=\frac{u}{2}$

Initial kinetic energy $=\frac{mu^2}{2}$

Final Kinetic Energy $=\frac{2m(\frac{u}{2})^2}{2}=\frac{mu^2}{4}$

change in kinetic energy $\Delta K.E.=\frac{mu^2}{2}-\frac{mu^2}{4}=\frac{mu^2}{4}$

change in kinetic energy will contribute in heat energy

thus fraction of kinetic energy converted in to heat $=\frac{heat\ energy}{Initial\ kinetic\ Energy} =\frac{\frac{mu^2}{4}}{\frac{mu^2}{2}}=\frac{1}{2}=0.5$

5 0

4 years ago