An experiment to measure the speed of sound was carried out. David, who is 200m from a large brick wall clapped two pieces of wood together many times, each time he heard the echo (reflected sound) he immediately clapped again. Maryam used a stopwatch to time how long it took for 10 claps and echos. Explain why they timed 10 clap/echoes and not just 1?

The chart shows the costs and shipping times for materials that a company needs to build a new product. which describes the best trade-off if the company needs to start building their product within the next two years? they should order the domestic materials because it is always best to choose the fastest shipping time. they should order the imported materials because it is always best to choose the lowest cost for materials. since the shipping time is longer, they should order the domestic materials because the additional cost is worth it to get the materials in time. even though the shipping time is longer, they should order the imported materials because they are less expensive and should arrive in plenty of time to build the product.