<p>how much work must be done to stop a 1100 kg car travelingat 115 km / h ?</p><p> w = ..... J</p><p> Thank you.</p>
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<p>A pen contains a spring with a spring constant of 250 N/m. When the tip of the pen is in its retracted position, the spring is compressed 5.0 mm from its unstrained length. In order to push the tip out and lock it into its writing position,the spring must be compressed an ad- ditional 6.0 mm. How much work is done by the spring force to ready the pen for writing? Be sure to include the proper algebraic sign with your answer.</p>
<p>A 15kg snowball is fired from a cliff 12.5m high. the snowball's inital velocity is 14.0m.s directed 41 degrees above the horizontal. A)How much work is done on the snowball by the gravitatinal force during its flight to the flat ground below the cliff? b) What is the change in the gravitational potential energy of the snowball-earth systems during the flight? c) If the gravitational potential energy is taken to be zero at the height of the cliff what is the value when the snowball reaches the ground?</p>
87.The force exerted by Earth on a particle of mass madistance r (r > RE) from the center of the Earthhasthe magnitudeofmgRE2/r2, where g=GME/RE2. a)Calculatethe work you must do to move the particle fromdistancer1 to r2.b) Show that when r1 = RE and r2=RE + h, the result can be written as W=mgRE2[(1/RE) - 1/(RE+h)].c) Show that when h << RE, the work givenisapproximated by W = mgh.