Awagon is rolling forward on level ground. friction is negligible. the person sitting in the wagon is holding a rock. the total mass of the wagon, rider, and rock is 95.5 kg. the mass of the rock is 0.290 kg. initially the wagon is rolling forward at a speed of 0.510 m/s. then the person throws the rock with a speed of 17.5 m/s. both speeds are relative to the ground. find the speed of the wagon after the rock is thrown directly forward.

Amajor impediment to wide acceptance of electric vehicles even on the part of people who use their cars almost exclusively for commuting is the inability to use their electric vehicles for occasional extended trips. in an attempt to make purchasing electric vehicles more attractive to commuters, one electric vehicle producer is planning to offer customers three days free rental of a conventional car for every 1,000 miles that they drive their electric vehicle. which of the following, if true, most threatens the plan's prospects for success? (a) many electric vehicles that are used for commercial purposes are not needed for extended trips. (b) because a majority of commuters drive at least 100 miles a week, the cost to the producer of making good the offer would add considerably to the already high price of electric vehicles. (c) the relatively long time it takes to recharge the battery of an electric vehicle can easily be fitted into the regular patterns of car use characteristic of commuters. (d) although electric vehicles are essentially emission-free in actual use, generating the electricity necessary for charging an electric vehicle's battery can burden the environment. (e) some family vehicles are used primarily not for commuting but for making short local trips, such as to do errands.