The woman is correct because it is the pace he is moving not walking.
Momentum = (mass) x (speed)
Original momentum = (700 kg) x (30 m/s) = 21,000 kg-m/s
Final momentum = (700 kg) x (15 m/s) = 10,500 kg-m/s
Change in momentum = - 10,500 kg-m/s .
Answer:
Matter can be recycled while energy cannot be recycled in an ecosystem.
Explanation:
Energy is lost in form of heat from one organism to another. The major energy in an ecosystem is from the sun (solar energy) which is taken by the producers. Once the sun stops generating energy, life will be difficult. Unlike the sun, matter can be recycled. Living things need non living things to survive. Matter can be 'nutrient' (which is non living). Nutrients are needed for life and growth. Nutrients include water, oxygen, carbon etc. An ecosystem nutrient cycle shows that decomposes are vital. Decomposers release nutrients when they break down dead organisms. These nutrients released by Decomposers are taken in by plants through the roots. The nutrients pass from producers (plants) to primary consumer (herbivores) when they feed on plants and then to higher levels consumers when they feed and digest the lower levels consumers and the producers. When they (the living things) grow and die, the nutrient cycle begins again.
