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2 years ago

10

A player kicks a football from ground level with an initial velocity of 27.0 30.0 above the horizontal Find the ball's maximum h

eight

1 answer:

stepladder [879]2 years ago

5 0

Answer:

Given

initial velocity (u) =27.030

Force of gravidity g) =9.8

Rtc maximum height Hmix =?

$sln \\ \ hmix = u {}^{2} \div 2g \\ 27.030 \div 2 \times 9 \\ \\ hmix = 38.025m$

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A football player kicks the ball at a 45 degree angle. Without an effect from the wind, the ball would travel 60.0m horizontally

Ronch [10]

B when the ball is at its maxium height

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3 years ago

A car is running at the speed of 45km/hr see a child 25 meter ahead and suddenly apllies a brakes. If the retradation of the car

kenny6666 [7]

Answer:

The car stops in 7.78s and does not spare the child.

Explanation:

In order to know if the car stops before the distance to the child, you take into account the following equation:

$x=x_o+v_ot-\frac{1}{2}at^2$ (1)

vo: initial speed of the car = 45km/h

a: deceleration of the car = 2 m/s^2

t: time

xo: initial distance to the child = 25m

x: final distance to the child = 0m

It is necessary that the solution of the equation (1) for time t are real.

You first convert the initial speed to m/s, then replace the values of the parameters and solve the quadratic polynomial for t:

$45\frac{km}{h}*\frac{1h}{3600s}*\frac{1000m}{1km}=12.5\frac{m}{s}$

$0=25+12.5t-2t^2\\\\2t^2-12.5t-25=0\\\\t_{1,2}=\frac{-(-12.5)\pm \sqrt{(-12.5)^2-4(2)(-25)}}{2(2)}\\\\t_{1,2}=\frac{12.25\pm 18.87}{4}\\\\t_1=7.78s\\\\t_2=-1.65s$

You take the first value t1 because it has physical meaning.

The solution for t is real, then, the car stops in 7.78s and does not spare the child.

4 0

3 years ago

Despite a very strong wind, a tennis player

Gnoma [55]

Answer:

Option 5. 1 and 3

Solution:

The only forces acting on the tennis ball after it has left contact with the racquet and the instant before it touches the ground are the force of gravity in the downward direction and the force by the air exerted on the ball.

The ball after it left follows the path of trajectory and as it moves forward in the horizontal direction the force of the air acts on it.

In the whole projectile motion of the ball, the acceleration due to gravity acts on the ball thus the force of gravity acts on the ball in the downward direction before it hits the ground.

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3 years ago

7. What is the velocity of an object that has a mass of 4.5 kilograms and

labwork [276]

Answer:

266.66 m/s

Explanation:

p=mv

1200=4.5v

v=266.66 m/s

7 0

2 years ago

5. The net external force on a rock of mass 4.2 kg is 8.0 N forward. Find the acceleration of the rock.

andreev551 [17]

Answer:

1.904

Explanation:

F= ma

8 = 4.2 a

a = 8/4.2

a = 1.904

6 0

2 years ago