A 50-g ball moving at 10 m/s in the +x direction suddenly collides head-on with a stationary ball of mass 100 g. If the collision is perfectly elastic, what is the velocity of each ball immediately after the collision?.

Panthers and leopards prey on deer in an ecosystem. for unknown reasons, the population of leopards increased drastically. what are the likely effects of this change on the species? 1. more food for panthers and more competition for leopards 2. less food and more competition for panthers 3. fewer deer and more competition for panthers 4. more food for deer and less competition for panthers and leopards 5. more food for leopards and less competition for panthers

In this food web, which group would increase in number if snakes were eliminated? a. producers b. decomposers c. primary consumers d. secondary consumers e. tertiary consumers

In 1999, the u.s. announced trade sanctions worth $116.8 million, targeting goods from france, germany, italy and denmark. the sanctions were in retaliation for a ban on u.s. hormone-treated beef by which organization?