The end of which era left many plants, insects, and salamander-like animals on the Earth?

a. the Precambrian time

c. the Paleozoic era

b. the Mesozoic era

d. the Cenozoic era

A 30.0 kg dolphin decelerates from 12.0 to 7.00 m/s in 2.60 s to join another dolphin in play. What average force (in N) was exerted to slow him if he was moving horizontally? (The gravitational force is balanced by the buoyant force of the water.

An inductor with L = 9.80 mH is connected across an ac source that has voltage amplitude 41.5 V. What value for the frequency of the source results in a current amplitude of 4.50 A?

Two astronauts, of masses 60 kg and 80 kg, are initially right next to each other and at rest in outer space. They suddenly push each other apart. How far has the heavier astronaut moved when the lighter astronaut has moved 12 m

A square current loop 4.9 cm on each side carries a 480 mA current. The loop is in a 0.60 T uniform magnetic field. The axis of the loop, perpendicular to the plane of the loop, is 30° away from the field direction.

The following students measure the density of a piece of lead three times. the density of lead is actually 8.9 g/cm3. considering all of the results, which person's results are both accurate and precise? a. jenny: 8.55 g/cm3, 8.34 g/cm3, 8.

X-rays UV light waves Sound waves Earthquake waves. All of these have which characteristic in common?

V=345m/s, 7210Hz, X=?

As a mercury atom absorbs a photon of energy, an electron in the atom changes from energy level d to energy level e. Determine the energy of the absorbed photon in electronvolts.

During an exothermic reaction, the energy given off comes from atoms being consumed mass being burned into energy the breaking and forming of bonds mass being created

Can electrostatic attract both pull and pull?