Getting errors while using fplot

Ive been working on a little assignment, however, when I go to plot the results I get some strange behaviour. I cant add color specififcations, line width specifications, limits, legend, or even a hold off without getting a massive yellow text box saying "Warning: Error updating ParametrizedFunctionLine" and as soon as I delete said things, the message dissapears.

Any idea on how I can fix this?

And the full code is this:

syms v(t) s(t)
g = 9.8;
EQv = diff(v) == -g;
cond = v(0) == 105;
v(t) = dsolve(EQv, cond)

v(t) = 

EQs = diff(s) == v(t);
cond = s(0) == 0;
s(t) = dsolve(EQs, cond)

s(t) = 

tmax = 150/7

tmax = 21.4286

syms vr(t) sr(t)
k = 0.003;
EQv2 = diff(vr) == -g-k*vr;
cond = vr(0) == 105;
vr(t) = dsolve(EQv2,cond)

vr(t) = 

EQs2 = diff(sr) == vr;
cond = sr(0) == 0

cond = 

sr(t) = dsolve(EQs2,cond)

sr(t) = 

fplot(s(t), [0 tmax], 'Color', 'blue', 'LineWidth', 2)
hold on
r = solve(sr(t)==0)

r = 

fplot(sr(t),[0 r], 'Color', 'red', 'LineWidth', 2)
legend('Sin resistencia','Con resistencia')
hold off

Warning: Error updating ParameterizedFunctionLine.

The following error was reported evaluating the function in FunctionLine update: Non-scalar in Uniform output, at index 1, output 1.
Set 'UniformOutput' to false.

Answer 1

[Chunru]

syms v(t) s(t)
g = 9.8;
EQv = diff(v) == -g;
cond = v(0) == 105;
v(t) = dsolve(EQv, cond)

v(t) = 

EQs = diff(s) == v(t);
cond = s(0) == 0;
s(t) = dsolve(EQs, cond)

s(t) = 

tmax = 150/7

tmax = 21.4286

tmax = 21.4286

tmax = 21.4286

syms vr(t) sr(t)
k = 0.003;
EQv2 = diff(vr) == -g-k*vr;
cond = vr(0) == 105;
vr(t) = dsolve(EQv2,cond)

vr(t) = 

EQs2 = diff(sr) == vr;
cond = sr(0) == 0

cond = 

sr(t) = dsolve(EQs2,cond)

sr(t) = 

fplot(s(t), [0 tmax], 'Color', 'blue', 'LineWidth', 2)
hold on
r = solve(sr(t)==0)

r = 

sr

sr(t) = 

fplot(sr(t),[0 double(r)], 'Color', 'red', 'LineWidth', 2)   % interval should be double to avoid warning
legend('Sin resistencia','Con resistencia')
hold off