Please answer this science question NO LINKS

What is the average speed of a car that travels 40 mph for 1 hour and 60 mph in another hour?

What object a collides with object b and bounces back its final momentum is?

This is important. 1. which of the following is an si base unit for measuring length? (2 points) inch gram meter mole 2. which of the following units for distance is an si unit? (2 points) centimeter foot inch yard 3. which of the following tools should a scientist use to measure an object in meters? (2 points) electronic balance pan balance tape measure thermometer