A few qustions i couldn't do in my HW... a bit of help please

I can't do these questions, a little help please.
Don't forget to use Radians on ur calculator.
I put the answers if its any help.



1. As a mass on a spring travels upwards through the equilibrium position, its velocity is 0.5m/s. Is the frequency of the pendulum is 1Hz what will the velocity of the bob be after 0.5s?
Answer is -0.5m/s

2. A long pendulum swings with a time period of 5s and an amplitude of 2m.
a) What is the maximum velocity of the pendulum?
b) What is the maximum acceleration of the pendulum?
Answers are a) 2.5 m/s b) 3.16 m/s^2

3) A mass on a spring oscillates with amplitude 5 cm and frequency 2 Hz. The mass is released from its highest point. Calculate the velocity of the mass after it has travelled 1 cm.
Answer is 0.37 m/s

4) A body oscillates with SHM of time period 2 s. What is the amplitude of the oscillation if its velocity is 1 m/s as it passes through the equilibrium position?
Answer is 0.318m

thx

Hello

1)
f=1
ω = 2pif = 2pi
the equation is y = Asin(2pi*t) and
v = A*2pi*cos(2pi*t)
when the bob goes through the equilibrium point, t = 0
0.5 = A*2pi(1)
A = 0.0795
find v at t = 0.5
v = 0.0795*2pi*cos(pi)
v = 0.0795*2pi(-1)
v = - 0.5 m/s
------------------
2)
find the length of the line:
T = 2pi*√(l/g)
(5/2pi)^2 = l/g
l = (5/2pi)^2*9.81
l = 6.212 m

amplitude = 2 m , this is the maximum horizontal distance from
the middle vertical. find the angle a between the vertical and the line:
sin (a) = 2/6.212 = 18.78°
and the tangential force at this maximum angle is
F = mg*sin(18.78)
and a = F/m = g*sin(18.78)
a = 3.1 m/s^2
----------------------
3)
f = 2 Hz
w = 2pif = 4pi
the mass is released at the highest point, therefore the equation is
y = 0.05cos(4pi*t)
find t when y = 0.04:
0.04 = 0.05cos(4pi*t)
0.8 = cos(4pi*t)