the height of an object after t seconds is given by f(t)=-5t^2+20t (a) find the height of the object after 2 seconds, and include the correct units with your answer. (b) find the average (vertical) velocity of the object on the time interval [0,2]. show your work, include the correct units, and. circle your final answer. (c) find the instantaneous velocity at t=2

The square pyramid has a volume of 441 cubic inches. what is the value of x? 1/7x is the height x is the base

John used linear combination to solve the system of equations shown. he did so by multiplying the first equation by -3 and the second equation by another number to eliminate the x-terms. what number did jonas multiply the second equation by? 4x-6y=23x+5y=11

Stu and ambrose are working together on a study of whether diet is related to students' mental health. first, they randomly select 10 students from the student center and 10 students from the office of counseling and psychological services. then, they ask students to rate their diet in terms of healthiness on a scale of 1-100 before completing a 20-item mental health survey. a) name one of the constructs being studied b) how was the construct you named above operationally defined in this experiment? e) was the variable you described above their independent variable, their dependent variable, or a controlled variable? d) what is a confounding variable? what is a potential confound in this study?