# Physics

A cyclist starts from rest and coasts down a 6.5∘{\rm ^\circ} hill. The mass of the cyclist plus bicycle is 95kg{\rm kg} . The cyclist has traveled 270m{\rm m} .What was the net work done by gravity on the cyclist? How fast is the cyclist going? Ignore air resistance.

1. 👍 0
2. 👎 0
3. 👁 602
1. Note:
the degree symbol is written as
& d e g ;
(suppress all spaces)

Difference in elevation, Δh
= 270m × sin(6.5°)
total mass (cyclist + bicycle), m
= 95 kg
total weight
= mg

Work done (on cyclist & bicycle)
=mgΔh

Component of force along slope, F
= mg cos(θ)
downward acceleration along slope, a
= F/m
= g cos(θ)

Consider the acceleration over distance d of 270 m
d=270 m
vi=0 (initial velocity)
vf (final velocity)
a=gcos(θ)
θ=6.5°
g=9.8 m/s²
m=95 kg

We can apply the kinematics equation
vf²=vi²+2ad
to solve for vf.

1. 👍 0
2. 👎 0
2. a=gsin(theta) not gcos(theta)

1. 👍 0
2. 👎 0

## Similar Questions

1. ### physics

A cyclist approaches the bottom of a gradual hill at a speed of 12.4 m/s. The hill is 6.7 m high and the cyclist estimates she is going fast enough to coast up and over it without peddling. Ignoring air resistance and friction,

asked by Anonymous on November 16, 2012
2. ### physics

A skier starts from rest at the top of a hill. The skier coasts down the hill and up a second hill, as the drawing illustrates. The crest of the second hill is circular, with a radius of 39.6 m. Neglect friction and air

asked by Anonymous on April 15, 2013
3. ### Physics

A skier starts from rest at the top of a hill. The skier coasts down the hill and up a second hill, as the drawing illustrates. The crest of the second hill is circular, with a radius of 38.3 m. Neglect friction and air

asked by Candy on February 29, 2012
4. ### physics

A skier starts from rest at the top of a hill. The skier coasts down the hill and up a second hill, as the drawing illustrates. The crest of the second hill is circular, with a radius of 38.1 m. Neglect friction and air

asked by susan on October 18, 2012
5. ### biomechanics

A cyclist is coasting up a hill. At t=0, the cyclist has a velocity of 14.27 m/s. If the acceleration of the cyclist is constant at -1.67 m/s2, how long will it take the cyclist to come to a complete stop? If the peak of the hill

asked by Alice on September 21, 2016
6. ### Physics

A cyclist coasts up a 10.3° slope, traveling 17.0 m along the road to the top of the hill. If the cyclist's initial speed is 9.90 m/s, what is the final speed? Ignore friction and air resistance. Any help would be great.

asked by Ryan on February 26, 2011
7. ### Physics

A cyclist approaches the bottom of a gradual hill at a speed of 14 m/s. The hill is 4.0 m high, and the cyclist estimates that she is going fast enough to coast up and over it without peddling. Ignoring air resistance and

asked by Peter on February 25, 2008
8. ### Physics

A cyclist approaches the bottom of a gradual hill at a speed of 20 m/s. The hill is 4.4 m high, and the cyclist estimates that she is going fast enough to coast up and over it without peddling. Ignoring air resistance and

asked by Zach on February 25, 2008
9. ### physics

A racing cyclist accelerates 5m/s² when she starts from rest. The total mass of the cyclist and her bicycle is 45kg. Calculate the resultant force that produces this acceleration

asked by help on February 24, 2015
10. ### math

a cyclist bikes at a speed of 6 m/s after rolling down a hill in 3 s. Of the cyclist has a constant acceleration of 2 m/s during the descent, what was the velocity of the cyclist at the top of the hill?

asked by abaza on October 20, 2014

More Similar Questions