Multiply the time by the acceleration due to gravity to find the velocity when the object hits the ground. If it takes 9.9 seconds for the object to hit the ground, its velocity is (1.01 s)*(9.8 m/s^2), or 9.9 m/s.

Explanation:really sorry if it wrong,i mean reallyyyyy

4 0

3 years ago

A river has a steady speed 0.500 m/s. A student swims upstream a distance of1.00 km and swims back to the starting point. a) If

Ivahew [28]

Answer:

a) 33.6 min

b) 13.9 min

c) Intuitively, it takes longer to complete the trip when there is current because, the swimmer spends much more time swimming at the net low speed (0.7 m/s) than the time he spends swimming at higher net speed (1.7 m/s).

Explanation:

The problem deals with relative velocities.

Call Vr the speed of the river, which is equal to 0.500 m/s
Call Vs the speed of the student in still water, which is equal to 1.20 m/s
You know that when the student swims upstream, Vr and Vs are opposed and the net speed will be Vs - Vr
And when the student swims downstream, Vr adds to Vs and the net speed will be Vs + Vr.

Now, you can state the equations for each section:

distance = speed × time
upstream: distance = (Vs - Vr) × t₁ = 1,000 m
downstream: distance = (Vs + Vr) × t₂ = 1,000 m

Part a). To state the time, you substitute the known values of Vr and Vs and clear for the time in each equation:

(Vs - Vr) × t₁ = 1,000 m
(1.20 m/s - 0.500 m/s) t₁ = 1,000 m⇒ t₁ = 1,000 m / 0.70 m/s ≈ 1429 s
(1.20 m/s + 0.500 m/s) t₂ = 1,000 m ⇒ t₂ = 1,000 m / 1.7 m/s ≈ 588 s
total time = t₁ + t₂ = 1429s + 588s = 2,017s
Convert to minutes: 2,0147 s ₓ 1 min / 60s ≈ 33.6 min

Part b) In this part you assume that the complete trip is made at the velocity Vs = 1.20 m/s

time = distance / speed = 1,000 m / 1.20 m/s ≈ 833 s ≈ 13.9 min

Part c) Intuitively, it takes longer to complete the trip when there is current because the swimmer spends more time swimming at the net speed of 0.7 m/s than the time than he spends swimming at the net speed of 1.7 m/s.

6 0

4 years ago

if a man hits a golf ball (0.2 kg) which accelerates at a rate of 20 m/s squared. what amount of force acted on the ball?

kkurt [141]

F = ma

We have mass = 0.2kg

and acceleration = 20 m/s^2

So..

F = (0.2)(20)

F = 4 N

6 0

3 years ago

El peso normal de un estudiante de secundaria es 725 N y el área de los dos zapatos que usa es de 412 cm2 . La presión medida qu

kotykmax [81]

Answer:

Presión = 175,97 N/m²

Explanation:

Dados los siguientes datos;

Peso del alumno (fuerza) = 725N

Área de zapatos = 412 cm² a metros cuadrados = 412/100 = 4.12 metros

Para encontrar la presión, usaríamos la siguiente fórmula;

Presión = fuerza / área

Presión = 725 / 4.12

Presión = 175,97 N/m²

8 0

3 years ago