Afirecracker shoots up from a hill 160 feet high with an initial speed of 90 feet per second. using the formula h(t) = −16t2 + vt + s, approximately how long will it take the firecracker to hit the ground?

Answer : t = 7.044 sec

Explanation :

It is given that,

Velocity,

distance,

When firecracker hits the ground hen H(t) = 0

So,

or

Solving this quadratic equation, we get

Neglecting negative values as time can't be negative.

Firecracker will take 7.044 sec to hit the ground.

a.metals can become magnetic if they have many spinning electrons that create magnetic fields.d.only some metals are attracted by magnets; these metals are called ferromagnetic.

d.wrapping an insulated wire around a metal with ferromagnetic properties and applying an electric current.