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Q: Engineeringing Physics ( No Answer,   1 Comment )
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 Subject: Engineeringing Physics Category: Science > Physics Asked by: pj4444-ga List Price: \$4.00 Posted: 01 Apr 2003 21:46 PST Expires: 05 Apr 2003 19:53 PST Question ID: 184693
 ```A man pushes a 16 kg lawn mower at a constant speed with a force F = 90 N directed along the handle, which is at an angle of 45° to the horizontal (see below). Calculate: a.the horizontal retarding force on the mower; b.the normal force exerted vertically upward on the mower by the ground; and c.the force the man must exert on the lawn mower to accelerate it from rest to 1.5 ms-1 in 2.5 seconds. Assume the same retarding force.```
 ```a) retarding force is the same as the horizontal force exerted by the man, that is 90/sqrt(2) N. 64 N b) the weight of the mower (16kg * 9.8 N/kg) plus the vertical force exerted by the man, which is 90/sqrt(2) N. 220 N c) net force is mass*acceleration. acceleration = 1.5/2.5 m/s^2 = .6 m/s^2, so net force is .6 m/s^2 * 16 kg = 9.6 N. In addition there is 90/sqrt(2) N retarding force. 73 N```