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icang [17]
3 years ago
5

A stone is thrown from the top of a building with an initial velocity of 20 m/s downward. The top of the building is 60 m above

the ground. How much time elapses between the instant of release and the instant of impact with the ground
Physics
1 answer:
erastova [34]3 years ago
6 0

Answer:

t = 2 s

Explanation:

In order to find the time taken by the stone to fall from the top of the building to the ground we can use 2nd equation of motion. 2nd equation of motion is as follows:

s = Vit + (0.5)gt²

where,

t = time = ?

Vi = Initial Velocity = 20 m/s

s = height of building = 60 m

g = 9.8 m/s²

Therefore,

60 m = (20 m/s)t + (0.5)(9.8 m/s²)t²

4.9t² + 20t - 60 = 0

solving this quadratic equation we get:

t = -6.1 s   (OR)   t = 2 s

Since, the time cannot be negative in magnitude.

Therefore,

<u>t = 2 s</u>

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A homeowner uses a snowblower to clear his driveway. knowing that the snow is discharged at an average angle of 40° with the hor
Nesterboy [21]

given that snow is projected at an angle of 40 degree

It range is given as a = 19 ft

a = 19 * 0.3048 = 5.8 m

now we can use the formula of horizontal range

R = \frac{v_o^2 sin2\theta}{g}

5.8 =\frac{ v_o^2 sin(2*40)}{9.8}

5.8 = \frac{v_o^2 * sin80}{9.8}

v_o^2 = 57.7

v_o = 7.6 m/s

<u>so its initial speed must be 7.6 m/s</u>

8 0
3 years ago
Calculate the recoil speed of a 1.4 kg rifle shooting 0.006 kg bullets with muzzle speed of 800 m/a.3.43 m/s
Angelina_Jolie [31]

Answer:

a) 3.43 m/s

Explanation:

Due to the law of conservation of momentum, the total momentum of the bullet - rifle system must be conserved.

The total momentum before the bullet is shot is zero, because they are both at rest, so:

p_i = 0

Instead the total momentum of the system after the shot is:

p_f = mv+MV

where:

m = 0.006 kg is the mass of the bullet

M = 1.4 kg is the mass of the rifle

v = 800 m/s is the velocity of the bullet

V is the recoil velocity of the rifle

The total momentum is conserved, therefore we can write:

p_i = p_f

Which means:

0=mv+MV

Solving for V, we can find the recoil velocity of the rifle:

V=-\frac{mv}{M}=-\frac{(0.006)(800)}{1.4}=-3.43 m/s

where the negative sign indicates that the velocity is opposite to direction of the bullet: so the recoil speed is

a) 3.43 m/s

5 0
3 years ago
An austrain who lived in vienna who composed graetest music for waltz dance<br>​
Stolb23 [73]
Johann Strauss II



hope this helps
6 0
3 years ago
Pretend you (80 kg) are making repairs on the outside of the International Space Station. You are floating 20 meters away from t
djyliett [7]

Answer:

32 seconds

Explanation:

m1 = 80 kg

m2 = 10 kg

v2 = 5m/s

According to the property of conservation of momentum, assuming that both you and the bag are stationary before the safety rope comes lose:

m_{1} v_{1} =m_{2} v_{2} \\80v_{1} =10*5 \\v_{1} = 0.625\ m/s

Since the space station is 20 meters away, the time taken to reach it is given by:

t = \frac{20}{0.625}\\t=32\ s

It takes you 32 seconds to reach the station.

7 0
3 years ago
A sample of nitrogen gas has a volume of 5.0 ml at a pressure of 1.50 atm. what is the pressure exerted by the gas if the volume
olchik [2.2K]

A sample of nitrogen gas has a volume of 5.0 ml at a pressure of 1.50 atm. what is the pressure exerted by the gas if the volume increases to 30.0 ml, at constant temperature is 0.25atm.

On constant temperature, the pressure and volume relation become constant before and after the change in quantitities have occurred.

According to Boyle's Law,

P₁V₁ = P₂V₂

where, P₁ is pressure exerted by the gas initially

V₁ is the volume of gas initially

P₂ is pressure exerted by the gas finally

V₂ is the volume of gas finally

Given,

P₁ = 1.5 atm

V₁ = 5 ml

V₂ = 30 ml

P₂ =?

On substituting the given values in the above equation:

P₁V₁ = P₂V₂

1.5 atm × 5 ml = P₂ × 30 ml

P₂ = 0.25 atm

Hence, pressure exerted by the gas is 0.25atm.

Learn more about Boyle's Law here, brainly.com/question/1437490

#SPJ4

8 0
2 years ago
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