Which is a chemical change

Which of the following is true about spinal reflex

Sound pulses emitted by a dolphin travel through 20°c ocean water at a rate of 1450 m/s. in 20°c air, these pulses would travel 342.9 m/s. how can you account for this difference in speed?

A little boy is standing at the edge of a cliff 1000 m high. He throws a ball straight downward at an initial speed of 20 m/s, and it falls straight down to the ground below.

By what amount does the 52-cm-long femur of an 73 kg runner compress at this moment? The cross-section area of the bone of the femur can be taken as 5.2*10-4m2 and its Young's modulus is 1.6*1010N/m2.

Where is the chart option found in the Excel application?

How do we use light in space?

What units are used for gravitational potential energy? Write the name, not the symbol.

A 7.5 kg block is placed on a table. If it's bottom surface area is 0.6m2, how much pressure does the block exert on the tabletop? A. 376.5 Pa B. 73.5 Pa C. 226.5 Pa D. 122.5 Pa

A boulder of mass 2000 kg is at the top of a cliff of height 220 m. Determine how fast the boulder will be moving when it strikes the dirt below.

Which of the following statements are true? Check all that apply. O A positive charge and a negative charge attract each other. O Electric charge is conserved. O Two positive charges attract each other. O A neutral object contains no charge.