A robot pushes a 50kg box with a forward force of 394N. He is opposed by 94N of friction.

On a cold day, when the air temperature is 0°c, you empty your lungs and take a deep breath, filling your lungs with 4.2 l of air. if you hold your breath until the temperature of the air in your lungs reaches 37°c, what is the volume of the air in your lungs at that point, assuming the pressure does not change?

Students design a model roller-coaster track. they place a rubber ball at the highest point on the track and let it go. the ball rolls along the track pulled only by the force of gravity. eventually, it comes to a stop. which change to the design will result in the ball moving the greatest distance?

Assume you measured the mass of the cart to be (500 ± 1) g and the mass of the additional mass you put on the cart to be (500 ± 1) g as well. since the scale you are using in the lab cannot measure objects heavier than 600g you will have to sum up individual pieces and propagate the error. so what would be the mass and the standard error of the cart and the mass