Solve the problem.
-An object is thrown upward from the top of a 160-foot building with an initial velocity of 48 feet per second. How long after the object is projected upward will it strike the ground? Use the equation
A) -2 sec
B) 160 sec
C) 5 sec
D) 2 sec

Question

Solve the problem.
-An object is thrown upward from the top of a 160-foot building with an initial velocity of 48 feet per second. How long after the object is projected upward will it strike the ground? Use the equation 
A) -2 sec 
B) 160 sec 
C) 5 sec 
D) 2 sec

Quizplus · Accepted Answer

Using the formula 11ebb63d_1be2_c9ce_b851_715b0162bf9d_TB8475_11, we can solve for time (t) when the object will strike the ground.

Let's plug in the given values:

h = -16t^2 + 48t + 160 (since the object is moving upwards, we use a negative value for acceleration due to gravity)

0 = -16t^2 + 48t + 160 (when the object strikes the ground, its height is 0)

-16t^2 + 48t + 160 = 0 (simplify by dividing all terms by -16)

t^2 - 3t - 10 = 0 (factor the quadratic equation)

(t - 5)(t + 2) = 0

t = 5 sec or t = -2 sec

Since time cannot be negative, we can disregard the -2 sec solution. Therefore, the object will strike the ground after 5 seconds. We can use the equation h=-16t^2+v0t+h0, where h is the height, t is the time, v0 is the initial velocity, and h0 is the initial height. Plugging in the given values, we get: 
-16t^2 + 48t + 160 = 0 
Solving for t using the quadratic formula, we get t = 5 or -2. Discarding the negative solution, we get t = 5 seconds, which is the time it takes for the object to strike the ground.

Solve the Problem. -An Object Is Thrown Upward from the Top of a Top