Explain the term Doppler effect and resonance​

When a 5.0kg cart undergoes a 2.2m/s increase in speed, what is the impulse of the cart

In the circuit shown below, with each bulb holding a resistance of 60 ohms, how many amps of current are flowing? express your number as a decimal.

An astronaut in space cannot use a scale or balance to weigh objects because there is no gravity. but she does have devices to measure distance and time accurately. she knows her own mass is 77.4 kg , but she is unsure of the mass of a large gas canister in the airless rocket. when this canister is approaching her at 3.50 m/s , she pushes against it, which slows it down to 1.30 m/s (but does not reverse it) and gives her a speed of 2.60 m/s . what is the mass of the canister?