a sewing machine needle moves up and down in simple harmonic moon with an amplitude of 1.27 cm and a frequency of 2.55 hz. what is the maximum speed of the needle.

=force × distance a. work b. velocity c. pressure d. momentum

Lacie kicks a football from ground level at a velocity of 13.9 m/s and at an angle of 25.0° to the ground. how long will the ball be in the air before it lands? how far will the football travel before it lands?

The first-order reaction a→2b+c has rate constant 0.538 s−1. if the initial concentration of a is 0.867 mol l−1, what is the half-life of the reaction in seconds? remember to use correct significant figures in your answer (round your answer to the nearest hundredth). do not include units in your response.