Posted by Serkhref on Thursday, May 2, 2013 at 6:15am.
1. (a) A frictionless car of mass 1.5 tonnes travels uphill along a slope at 20º to the horizontal for 0.5 km at 20 km per hour.
(i) How much work does the engine do on the car?
(ii) What power does the engine supply?
(b) The car the rolls back down the hill with the engine turned off. How fast is it travelling when it has rolled back to its starting position?
(c) The car continues to roll a further 0.5 km down the slope until it hits a solid wall, whereupon it is brought to rest in a distance of 20 cm as the front of the car crumples.
(i) What impulse is applied to the wall?
(ii) Assuming uniform deceleration, what is the average braking force applied to the car by the wall?
(d) If the driver had noticed the wall when the car had rolled back as far as the starting point and had applied the brakes at that point, what average braking force and power would have been required to stop the car just as it reached the wall?
2. A car travels northeastwards for 2.5 km, accelerating with constant acceleration from stationary to 80 km per hour over the first 0.4 km and then travelling at constant velocity and finally breaking with constant deceleration to 5 km per hour over the final 0.2 km, at which point it turns 65º to the south. It then travels for another 3.7 km, initially accelerating to 65 km per hour for 0.28 km and then travelling at constant velocity before finally coming to rest by braking with constant deceleration for 10 s.
(a) Represent this journey accurately on distancetime, speedtime and accelerationtime graphs.
(b) Calculate the total distance and final displacement, the time taken for the journey, the average speed and the average velocity.

Physics  PsyDAG, Thursday, May 2, 2013 at 1:23pm
Indicate your specific subject in the "School Subject" box, so those with expertise in the area will respond to the question. We are not psychic.
Secondly, we do not do your homework for you. Although it might take more effort to do the work on your own, you will profit more from your effort. We will be happy to evaluate your work though.
Answer This Question
Related Questions
 physics  A car travels along a roadwith a speed of v=25 m/s (about 50 mi/h). ...
 physics  1. A car is coasting backwards downhill at a speed of 3.0 m/s when ...
 physics  A car is coasting backwards downhill at a speed of 2.6 m/s when the ...
 physics  A car is coasting backwards downhill at a speed of 3.2 m/s when the ...
 physics  find the power of an engine in kilowatts which pulls a train of mass ...
 Physics  A 1200 kg car accelerates to the right at 7m/s2 along a special ...
 Physics  Steel Phantom is a roller coaster in Pennsylvania that, like the ...
 physics  Cars A and B are racing each other along the same straight road in the...
 11th grade  a race car travels along a raceway at a constant velocity of 200 km...
 Physics  A car travels at a speed of 25 m/s on a flat stretch road. The driver ...
More Related Questions