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3 years ago

15

PLEASE PLEASE PLEASE HELP ME, I AM FREAKING OUT BECAUSE REPORT CARDS ARE COMMING SOON AND I REALLY NEED HELP!

1 answer:

anyanavicka [17]3 years ago

6 0

Baking soda added to water raises the temperature slightly. Chemical reactions are either endothermic or exothermic. Endothermic means you have to put energy in to make the reaction go while exothermic means there's energy left over. Left over heat will raise the temperature. Baking soda and water is exothermic and so the water gets a little warmer. This is because the binding energy of the chemical bonds of the products has an excess over the binding energy of the components. Therefore, energy is released and the water warms up.

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A rifle with a weight of 25 N fires a 4.0 g bullet with a speed of 290 m/s.

Ugo [173]

Answer:

Explanation:

Given

Weight of rifle $W=25\ N$

mass of rifle $M=\frac{25}{10}=2.5\ kg$

mass of bullet $m=4\ gm$

speed of bullet $u=290\ m/s$

As there is no net force on the bullet-rifle system therefore momentum is conserved

$0=Mv+mu$

$v=-\frac{mu}{M}$

$v=-\frac{4\times 10^{-3}\times 290}{2.5}$

$v=-0.464\ m/s$

i.e. opposite to the direction of bullet speed

(b)Weight of Man $=750\ N$

Combined weight of man and rifle $=750+25=775\ N$

mass of man-rifle system $M'=\frac{775}{10}=77.5\ kg$

Now man and rifle combinedly recoil

therefore

$0=(M')v '+mu$

$v'=-\frac{mu}{M'}$

$v'=-\frac{4\times 10^{-3}\times 290}{77.5}$

$v'=0.0149\ m/s$

3 0

4 years ago

Mr Yadav buys a radio for Rs 640 and sells it for Rs 672 Find it's profit<br><br>

Arisa [49]

Answer:

32

Explanation:

672-640=32

7 0

3 years ago

A vehicle approaches a set of traffic lights with a speed of 15m/s. When 50m from the lights the driver brakes and comes to a re

sattari [20]

Answer:

–2.25 m/s²

Explanation:

From the question given above, the following data were obtained:

Initial velocity (u) = 15 m/s

Distance travelled (s) = 50 m

Final velocity (v) = 0 m/s

Deceleration (a) =?

v² = u² + 2as

0² = 15² + (2 × a × 50)

0 = 225 + 100a

Collect like terms

0 – 225 = 100a

– 225 = 100a

Divide both side by 100

a = –225/100

a = –2.25 m/s²

Thus, the deceleration of the vehicle is –2.25 m/s²

3 0

3 years ago

Plz give me the answer of qiestion ofno 31

77julia77 [94]

The resistance between A and B is 10 ohms.

5 0

3 years ago

A proton is released from rest at x=5 cm. what direction does it move?

Veronika [31]

Down to the left, down the the right, criss cross!

6 0

3 years ago