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2 years ago

A 4 kg bowling ball rolls at a speed of 5 m/s on the roof of a building that is 30 meters tall. What is its kinetic energy?

Physics

1 answer:

klasskru [66]2 years ago

3 0

ans: B

Kinetic energy = $\frac{1}{2} mv^{2}$

= $\frac{1}{2} (4)(5^{2} )$

= 50J

ps. the height will only affect its potential energy, not kinetic.

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A 92-kg fullback moving south with a speed of 5.8 m/s is tackled by a 110-kg lineman running west with a speed of 3.6 m/s. Assum

MariettaO [177]

Answer:

The speed and direction of the two players immediately after the tackle are 3.3 m/s and 53.4° South of West

Explanation:

given information:

mass of fullback, $m_{x}$ = 92 kg

speed of full back, $v_{x}$ = 5.8 to south

mass of lineman, $m_{y}$ =110 kg

speed of lineman, $v_{y}$ = 3.6

according to conservation energy,

assume that the collision is perfectly inelastic, thus

initial momentum = final momentum

$P_{ix}$ = $P_{x}$ '

m₁v₁ = (m₁+m₂) $v_{x}$ '

$v_{x}$ ' = m₁v₁/(m₁+m₂)

= (92) (5.8)/(92+110)

= 2.64 m/s

$P_{iy}$ = $P_{y}$ '

m₂v₂ = (m₁+m₂) $v_{y}$ '

$v_{y}$ ' = m₁v₁/(m₁+m₂)

= (110) (3.6)/(92+110)

= 1.96 m/s

thus,

$v$ ' = √ $v_{x}$ '²+ $v_{y}$ '²

= 3.3 m/s

then, the direction of the two players is

θ = 90 - tan⁻¹( $v_{y}$ '/ $v_{x}$ ')

= 90 - tan⁻¹(1.96/2.64)

= 53.4° South of West

7 0

2 years ago

A car travels at a constant speed up a ramp making an angle of 28 degrees with the horizontal component of velocity is 40 kmh^-1

Hoochie [10]

Answer:

Vx = 35.31 [km/h]

Vy = 18.77 [km/h]

Explanation:

In order to solve this problem, we must decompose the velocity component by means of the angle of 28° using the cosine function of the angle.

$v_{x} = 40*cos(28)\\V_{x} = 35.31 [km/h]$

In order to find the vertical component, we must use the sine function of the angle.

$V_{y}=40*sin(28)\\V_{y} = 18.77 [km/h]$

7 0

2 years ago

Manmade global warming is caused by what?

kirill [66]

Human activities is the main reason of global warming such as factories and cars that causes carbon dioxide , carbon monoxide and other toxic gases

4 0

2 years ago

How can an object become charged

morpeh [17]

Answer:

An object gets charged when it's atoms lose or gain an electron to become an ion. For example: ... This means that the fur loses it's electrons to the plastic rod and both objects are now charged. The fur is positively charged because it lost electrons and the rod is negatively charged because it gained electrons

Explanation:

comment how it helps

3 0

2 years ago

Read 2 more answers

As shown in the figure below, a bullet is fired at and passes through a piece of target paper suspended by a massless string. Th

NikAS [45]

Answer:

M = 0.730*m

V = 0.663*v

Explanation:

Data Given:

$v_{bullet, initial} = v\\v_{bullet, final} = 0.516*v\\v_{paper, initial} = 0\\v_{paper, final} = V\\mass_{bullet} = m\\mass_{paper} = M\\Loss Ek = 0.413 Ek$

Conservation of Momentum:

$P_{initial} = P_{final}\\m*v_{i} = m*0.516v_{i} + M*V\\0.484m*v_{i} = M*V .... Eq1$

Energy Balance:

$\frac{1}{2}*m*v^2_{i} = \frac{1}{2}*m*(0.516v_{i})^2 + \frac{1}{2}*M*V^2 + 0.413*\frac{1}{2}*m*v^2_{i}\\\\0.320744*m*v^2_{i} = M*V^2\\\\M = \frac{0.320744*m*v^2_{i} }{V^2} ....... Eq 2$

Substitute Eq 2 into Eq 1

$0.484*m*v_{i} = \frac{0.320744*m*v^2_{i} }{V^2} *V \\0.484 = 0.320744*\frac{v_{i} }{V} \\\\V = 0.663*v_{i}$

Using Eq 1

$0.484m*v_{i} = M* 0.663v_{i}\\\\M = 0.730*m$

7 0

2 years ago