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2 years ago

A 60 kg bicyclist going 2 m/s increased his work output by 1,800 J. What was his final velocity?

Physics

2 answers:

Alinara [238K]2 years ago

6 0

<em>8 </em>was the correct answer, thanks

Bas_tet [7]2 years ago

3 0

Bicyclist initial kinetic energy is Ek=(1/2)*m*v² where m is his mass and v is his speed and that is equal to:

Ek=(1/2)*60*2²=120 J.

When we add the increased work output, we get the total kinetic energy:

Ek(total)=Ek+W= 120 J + 1800 J= 1920 J

So Ek(total)=1920 J = (1/2)*m*V² where V is the speed after the bicyclist increased his work output. So lets solve for V:

(1/2)*60*V²=1920

30*V²=1920, we divide by 30,

V²=64, and take the square root of both sides,

V=8 m/s.

So the speed of the bicyclist after the increased work output is V=8 m/s.

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A 200 g hockey puck is launched up a metal ramp that is inclined at a 30° angle. The coefficients of static and kinetic friction

Vaselesa [24]

Answer:

H=1020.12m

Explanation:

From a balance of energy:

$\frac{m*Vo^2}{2} -mg*H=-Ff*d$ where H is the height it reached, d is the distance it traveled along the ramp and Ff = μk*N.

The relation between H and d is given by:

H = d*sin(30) Replace this into our previous equation:

$\frac{m*Vo^2}{2} -mg*d*sin(30)=-\mu_k*N*d$

From a sum of forces:

N -mg*cos(30) = 0 => N = mg*cos(30) Replacing this:

$\frac{m*Vo^2}{2} -mg*d*sin(30)=-\mu_k*mg*cos(30)*d$ Now we can solve for d:

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6 0

1 year ago

Read 2 more answers

A ball is dropped from the top of an eleven-story building to a balcony on the ninth floor. In which case is the change in the p

lozanna [386]

Answer:

at the top of the 9 story building i think

Explanation:

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2 years ago

A football player kicks a 0.41-kg football initially at rest; and the ball flies through the air. If the kicker's foot was in co

LUCKY_DIMON [66]

Answer:

Average force on the football = 168.82 N

Explanation:

Force = Mass x Acceleration

F = ma

Mass, m = 0.41 kg

We have equation of motion, v = u + at

Initial velocity, u = 0 m/s

Final velocity, v = 21 m/s

Time, t = 0.051 s

Substituting

21 = 0 + a x 0.051

a = 411.76 m/s²

Substituting in force equation,

F = ma = 0.41 x 411.76 = 168.82 N

Average force on the football = 168.82 N

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1 year ago

A 72 kg skydiver is descending on a parachute. His speed is still increasing at 1.2 m/s2. What are the magnitude and direction o

frozen [14]

Answer:

86.4 N downward

Explanation:

Force: This can be defined as the product of mass and acceleration of a body.

The S.I unit of Force is Newton(N).

The Expression of force is given as,

F = ma ................ Equation 1

Where F = force of the parachute harness, m = mass of the skydiver, a = acceleration of the skydiver.

Given: m = 72 kg, a = 1.2 m/s²

Substitute into equation 1

F = 72(1.2)

F = 86.4 N down ward.

Hence the force on the parachute harness = 86.4 N downward

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2 years ago

A circuit node has current ia entering and currents ib and ic exiting, where it is known that ia=5 ma and ib=9 ma. what is curre

Rudik [331]

The current is the flow of electrons. It is expressed as Coulombs per second, or Amperes. Since it is a flow, all that comes in must go out. The basis here is the node. Since ia is the full flow, it must be greater than ib or ic. So, I think the given information is wrong. It should be ia = 9 mA and ib=5 mA.

Current entering = Current leaving
ia = ib + ic
9 mA = 5 mA + ic
ic = 9 mA - 5 mA = 4 mA

8 0

2 years ago